Arthur F. Stucchi

Pathologic features and clinical significance of "backwash" ileitis in ulcerative colitis.

Patients with ulcerative colitis (UC) may develop inflammation in the distal ileum thought to be due to “backwash” of cecal contents (“backwash ileitis”). However, a systematic analysis of ileal changes in UC has never been performed, and the prevalence and criteria for “backwash” ileitis have not been defined. The aim of this study was to evaluate the prevalence and spectrum of inflammatory changes in the ileum in patients with UC and to correlate ileal changes with outcome after total proctocolectomy and ileal pouch-anal anastomosis. Routinely processed ileocolonic resection specimens from 200 consecutive patients with clinically and pathologically confirmed UC were evaluated for a wide variety of pathologic features in the ileum and colon. The ileal data were correlated with both the clinical features and the pathologic findings in the colon. Follow-up data were obtained to confirm absence of Crohns disease and to evaluate outcome of ileo-anal pouches. Overall, 34 of 200 (17%) UC patients had inflammatory changes in the ileum (male/female ratio, 16/18; mean age, 42 years); 32 of 34 (94%) had pancolitis, which was significantly higher than the rate of pancolitis (39%) in patients without ileal disease (N = 166) (P < 0.001), but there were no other differences between patients with or without ileal pathology. In the colon, 22 of 34 (65%) patients had severe activity. Ileal changes included villous atrophy and crypt regeneration without increased inflammation (N = 3), increased neutrophilic and mononuclear inflammation in the lamina propria (N = 6), patchy cryptitis and crypt abscesses (N = 21) and focal superficial surface erosions (N = 4), some with pyloric metaplasia (N = 2 of 4). In general, the severity of ileal changes paralleled the severity of colonic activity. However, 2 of 4 (50%) patients with superficial erosions in the ileum had subtotal or left-sided colitis only, and had only mild colonic activity. Other cases showed only mild to moderate colonic activity and patchy or discontinuous involvement of the distal ileum. Upon follow-up of patients with erosions (mean, 48.5 months; range, 26-102 months), none developed manifestations of Crohns disease anywhere in the gastrointestinal tract. The presence of inflammatory changes in the ileum had no effect on the prevalence of pouch complications or on the occurrence of dysplasia or cancer. Ileal changes in UC are not uncommon (prevalence, 17%), are generally mild in nature (villous atrophy, increased inflammation, scattered crypt abscesses), and are not associated with an increased rate of ileo-anal pouch complications, dysplasia, or carcinoma. In some cases, our findings are consistent with a backwash etiology. However, rarely, ileal erosions may occur in patients without cecal involvement, which may indicate that other pathogenetic mechanisms should be considered in the etiology of ileitis in UC patients.

Statins (HMG-CoA reductase inhibitors) decrease postoperative adhesions by increasing peritoneal fibrinolytic activity.

Objectives:The aims of this study were to determine if statins reduce adhesion formation in vivo and to identify the mechanism of action in vitro. Background:Intraperitoneal adhesions develop in up to 95% of patients following laparotomy. Adhesions are reduced by mechanisms that up-regulate fibrinolysis within the peritoneum. Statins promote fibrinolysis in the cardiovascular system and may play a role in the prevention of adhesions. Methods:Adhesions were induced in rats (n = 102) using our previously described ischemic button model. Rats received vehicle (controls), lovastatin (30 mg/kg), or atorvastatin (30 mg/kg) as a single intraperitoneal dose at the time of laparotomy. Animals were killed and adhesions were quantified at day 7. Peritoneal fluid and tissue were collected at day 1 to measure tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) by real-time PCR and ELISA. To assess the effects of statins on wound healing, burst pressures were measured in anastomoses of the colon. The effects of lovastatin on tPA and PAI-1 production were measured in vitro in human mesothelial cells (HMC) in the presence or absence of mevalonate (MVA), geranylgeranyl-pyrophosphate (GGPP) and farnesyl-pyrophosphate (FPP), all intermediates in the cholesterol pathway downstream of HMG-CoA. The effect of a Rho protein inhibitor, exoenzyme C3 transferase, on tPA production was also determined. Results:Lovastatin and atorvastatin reduced adhesion formation by 26% and 58%, respectively (P < 0.05), without affecting anastomotic burst pressure. At 24 hours, tPA mRNA levels in peritoneal tissue and tPA activity in peritoneal fluid from lovastatin-treated animals were increased by 57% and 379%, respectively (P < 0.05), while PAI-1 levels were unchanged. HMC incubated with either lovastatin or atorvastatin showed concentration-dependent increases in tPA production and decreases in PAI-1 production (P < 0.05). These lovastatin-induced changes in tPA and PAI-1 production were significantly reversed by the addition of MVA, GGPP, and FPP. The Rho protein inhibitor increased tPA production and rescued tPA production from the inhibitory effect of GGPP. Conclusion:These data suggest that statins administered within the peritoneum can up-regulate local fibrinolysis, while the in vitro studies show that this effect may be mediated, in part, by intermediates of the cholesterol biosynthetic pathway that regulate Rho protein signaling.

NF-κB Activation Precedes Increases in mRNA Encoding Neurokinin-1 Receptor, Proinflammatory Cytokines, and Adhesion Molecules in Dextran Sulfate Sodium–Induced Colitis in Rats

Nuclear factor kappa B (NF-κ B) plays a key role in initiating inflammation associated with colitis. A systematic study was conducted in the rat DSS colitis model to determine the temporal relationship between NF-κ B activation and expression of substance P (SP), neurokinin-1 receptor (NK-1R), proinflammatory cytokines, and adhesion molecules. Rats were given 5% DSS in their water and sacrificed daily for 6 days. Colon tissue was collected for assessment of histological changes, NF-κ B activation, myeloperoxidase (MPO) activity, and expression of NK-1R, SP, TNFα, IL-1β, VCAM-1, ICAM-1, E-selectin, CINC-1, MIP-1α, and iNOS. NF-κ B activation increased, biphasically, on Day 1 and again on Days 4–6. The mRNA levels for ICAM-1, CINC-1, IL-1β, TNFα, VCAM-1, and NK-1R rose significantly (P< 0.05) by 2–4 days. Increased iNOS mRNA levels, MPO activity, and mucosal damage occurred on Day 6. These data demonstrate that NF-κ B activation substantially precedes the onset of physical disease signs and active inflammation.

Use of a novel vitamin D bioavailability test demonstrates that vitamin D absorption is decreased in patients with quiescent crohn's disease†‡§

Background: Vitamin D deficiency is a common problem in patients with Crohns disease (CD). The aim of this study was to determine the ability of normal subjects and patients with quiescent CD to absorb vitamin D2 using a novel vitamin D bioavailability test. In addition, we evaluated whether the location of disease or previous surgery had any influence on the bioavailability of vitamin D2 in CD patients. Methods: Ten normal subjects (50% female) and 37 CD patients with quiescent disease (51% female) were included in this study. Subjects who recently received any vitamin D2 were excluded. The vitamin D bioavailability test was performed in all subjects. After a baseline blood draw, all subjects were then given a single 50,000 IU oral dose of vitamin D2 in a capsule formulation and had their blood drawn 12 hours later to determine serum vitamin D2, which reflected their vitamin D2 absorption capacity. Results: Forty‐two percent and 29% of CD patients were found to be either vitamin D‐deficient (25‐hydroxyvitamin D [25(OH)D] ≤20 ng/mL] or insufficient [25(OH)D 21–29 ng/mL], respectively. Twelve hours after ingesting 50,000 IU vitamin D2, vitamin D2 levels rose from a baseline of 0.7 ± 0.7 ng/mL (mean ± SEM) to 49.8 ± 3.0 ng/mL in normal subjects. In CD patients, baseline vitamin D2 levels rose from 0 ng/mL to 34.8 ± 2.8 ng/mL. CD patients had on average a 30% decrease in their ability to absorb vitamin D2 (P = 0.01). Moreover, we found a wide variability of vitamin D2 bioavailability in CD patients. Analysis of variance (ANOVA) revealed no statistical difference of vitamin D2 bioavailability between patients in the CD subgroup stratified by the location of disease, the type of surgery, and receiving or not receiving surgery. Conclusions: More than 70% of the patients with quiescent CD were vitamin D‐deficient or insufficient. The ability to absorb vitamin D2 in CD patients is unpredictable and the only way to determine this is to perform a vitamin D bioavailability test. Use of this test may guide clinicians in administering the appropriate therapeutic dose of vitamin D for treating vitamin D deficiency in patients with CD. (Inflamm Bowel Dis 2011;)

A new transcription factor that regulates TNF-α gene expression, LITAF, is increased in intestinal tissues from patients with CD and UC

Background: The proinflammatory cytokine tumor necrosis factor‐&agr; (TNF‐&agr;) plays a key role in the pathogenesis of Crohns disease (CD) and ulcerative colitis (UC). Recently, a new transcription factor termed LITAF (lipopolysaccharide‐induced TNF‐&agr; factor) was shown to mediate TNF‐&agr; expression in human macrophages by direct binding to specific sequences in the promoter region of the TNF‐&agr; gene. Methods: In this report, we identified LITAF in resected ileal and colonic tissues from patients with CD and UC by immunohistochemistry, real‐time polymerase chain reaction, and Western blot analysis. LITAF expression in inflamed and noninflamed areas of the tissues was compared. Results: This is the first demonstration of LITAF, a newly discovered transcription factor that regulates TNF‐&agr; gene transcription in ileal and colonic tissues from patients with either CD or UC. LITAF immunostaining was localized to lamina propria macrophages and was markedly increased relative to tissues from controls without inflammatory bowel disease. In patients with CD, a 5‐fold increase in LITAF mRNA was measurable in noninflamed colonic tissues compared with controls without inflammatory bowel disease. LITAF mRNA in tissues from inflamed areas of the colon was increased by an additional 60% compared with noninflamed tissues. In patients with UC, LITAF mRNA levels in colonic tissues resected from noninflamed areas were elevated 15‐fold above nondisease controls, but they were not different in tissues resected from inflamed areas. Western blot analysis showed that in patients with CD, there was a marked increase in LITAF protein in inflamed areas compared with noninflamed areas. LITAF protein levels were not different between noninflamed and inflamed tissues obtained from patients with UC. TNF‐&agr; mRNA and protein levels paralleled LITAF. Similarly, in inflamed ileal tissues from patients with CD, LITAF is also localized to lamina propria macrophages. LITAF mRNA and LITAF protein were significantly increased in inflamed ileal tissues compared with noninflamed areas. Conclusions: LITAF is readily detectable in ileal and colonic tissues from patients with either CD or UC, is significantly elevated above controls, and is localized to macrophages, a major source of TNF‐&agr;. These data provide strong evidence of a role for LITAF in the pathophysiological regulation of the TNF‐&agr; gene and underscore the potential value of anti‐LITAF strategies in the clinical management of these diseases.

Hyperactivated B cells in human inflammatory bowel disease

IBD is characterized by a chronic, dysregulated immune response to intestinal bacteria. Past work has focused on the role of T cells and myeloid cells in mediating chronic gastrointestinal and systemic inflammation. Here, we show that circulating and tissue B cells from CD patients demonstrate elevated basal levels of activation. CD patient B cells express surface TLR2, spontaneously secrete high levels of IL‐8, and contain increased ex vivo levels of phosphorylated signaling proteins. CD clinical activity correlates directly with B cell expression of IL‐8 and TLR2, suggesting a positive relationship between these B cell inflammatory mediators and disease pathogenesis. In contrast, B cells from UC patients express TLR2 but generally do not demonstrate spontaneous IL‐8 secretion; however, significant IL‐8 production is inducible via TLR2 stimulation. Furthermore, UC clinical activity correlates inversely with levels of circulating TLR2+ B cells, which is opposite to the association observed in CD. In conclusion, TLR2+ B cells are associated with clinical measures of disease activity and differentially associated with CD‐ and UC‐specific patterns of inflammatory mediators, suggesting a formerly unappreciated role of B cells in the pathogenesis of IBD

Histologic predictors of pouchitis in patients with chronic ulcerative colitis

Inflammation of ileal reservoir mucosa (“pouchitis”) is a common sequelae in ulcerative colitis (UC) patients who have had a colectomy with ileal pouch anal-anastomosis (IPAA). Although several clinical, genetic, and laboratory parameters have been evaluated, reliable pathologic predictors for the development of pouchitis are lacking. The purpose of this case–control study was to determine whether there are any pathologic features in UC colectomy specimens that may help predict the subsequent development of pouchitis after an IPAA procedure. The study group consisted of 39 UC patients (male/female ratio: 21/18, mean age: 35 years), who had at least 1 episode of pouchitis after an IPAA procedure during the follow-up period (mean: 57 months, range: 12–121 months). There were 26 control patients (male/female ratio: 11/15, mean age: 37 years), all of whom also underwent a total colectomy and IPAA procedure for UC, but did not develop pouchitis during the follow-up period (mean: 78 months, range: 14–223 months). Routinely processed tissues from each colectomy specimen were evaluated for a variety of histologic features, such as extent of colitis, severity of colitis, extent of severe colitis, type and extent of ulceration, presence and severity of appendiceal inflammation, and the presence of active ileitis, and compared between the study and control patients. Pathologic features that were associated with the subsequent development of pouchitis included the presence of severe colitis that extended into the cecum (severe pancolitis), which was present in 7/39 (18%) pouchitis patients, but in none (0%) of the control patients (P = 0.03), early fissuring ulcers [9/39 (23%) pouchitis cases versus 1/26 (4%) controls (P = 0.04)], active inflammation of the appendix [20/32 (63%) pouchitis patients versus 7/19 (31%) controls (P = 0.03)], and appendiceal ulceration [13/32 (41%) pouchitis patients versus none (0%) of the controls (P = 0.002)]. No significant differences in patient gender or age, depth or extent of ulceration, or the presence or absence of “backwash ileitis” were identified between the 2 groups. In conclusion, there are several histologic features in colectomy specimens from UC patients who have undergone an IPAA procedure that may help predict the subsequent development of pouchitis. Of these features, appendiceal ulceration is highly associated with pouchitis.

Anti — Saccharomyces cerevisiae antibodies are associated with the development of postoperative fistulas following ileal pouch-anal anastomosis

Although serologic testing for perinuclear antineutrophil cytoplasmic antibodies (pANCA) and anti-Saccharomyces cerevisiae antibodies (ASCA) is reportedly useful in distinguishing ulcerative colitis (UC) from Crohn’s disease (CD), there are few and conflicting reports assessing their utility in predicting post-operative complications after ileal pouch-anal anastomosis (IPAA). We examined the associations between postoperative complications such as pouchitis or fistulas and pANCA and ASCA antibodies in a group of patients who underwent IPAA for UC. We conducted a retrospective chart review of 34 patients initially diagnosed with UC (four of these patients had a diagnosis of indeterminate colitis) who underwent IPAA by a single surgeon, and who had pANCA and ASCA antibody levels measured during their clinical course. Study patients were assigned to four groups based on the pattern of antibody reactivity: pANCA+/ASCA- (16 patients), pANCA-/ASCA+ (nine patients), pANCA+/ASCA+ (five patients), and pANCA-/ASCA- (four patients). The median length of follow-up was 16 months (3–144 months). None of the patients (0 of 16) who were pANCA+/ASCA- had their preoperative diagnosis of UC changed after a median follow-up of 14 months (3–118 months). Of the nine patients with a preoperative diagnosis of UC who were pANCA-/ASCA+, four patients (44%) had their diagnosis changed postoperatively to CD based on clinical findings, with a median follow-up: 15 months (5–98 months). Of 16 patients who underwent IPAA and who were pANCA+/ASCA-, 15 of 16 (93.75%), were free of fistulas postoperatively, with a median follow-up of 14 months (3–118 months). Of nine patients with a preoperative diagnosis of UC who underwent IPAA and who were pANCA-/ASCA+, four of nine (44%; p=0.04) developed fistulas postoperatively, with a median length of follow-up of 55 months (15–67 months). No relationship between serologic profiles or antibody titer levels and the development of pouchitis was identified. In a cohort of patients undergoing IPAA for UC, serologic profiles may be useful in identifying patients at risk of postoperative fistula formation. Patients who were pANCA-/ASCA+ were at increased risk for the development of fistulas postoperatively compared to patients who were pANCA+/ASCA-, and were also more likely to have their diagnosis changed postoperatively to CD. A larger study is needed to validate these observations.

Role of transforming growth factor beta-1 in peritonitis-induced adhesions.

Peritonitis is a major cause of intra-abdominal adhesion formation. The overexpression of transforming growth factor beta-l (TGF-Pl), a potent mitogen, chemoattractant, and stimulant for collagen synthesis by fibroblasts, has been linked to tissue fibrosis at various sites throughout the body including peritoneal adhesion formation. Hence we hypothesized that the mechanism(s) involved in peritonitis-induced adhesion formation may be mediated through the upregulation of TGF-β expression. Peritonitis was induced in rats by cecal ligation and puncture, while a control group underwent sham operation. Adhesions were scored and harvested from both groups at 0,6 and 12 hours and at 1,2,4, 7, and 28 days. Tissue expression of TGF-PI mRNA was determined by quantitative reverse transcription-polymerase chain reaction and TGF-β protein was localized by immunohistochemical analysis. Serum and peritoneal fluid TGF-β concentrations were quantified by enzyme-linked immunosorbent assay. Compared with sham operation, peritonitis was associated with a significantly greater incidence of abdominal adhesions and a significant increase in the levels of TGF-β 1 mRNA expression at days 2,4, and 7. Immunostaining intensity of TGF-β in adhesions from the peritonitis group also steadily rose through day 7. In peritoneal fluid, the ratio of active:total TGF-βl was significantly increased in the peritonitis group on days 1, 2, and 4 compared with the sham group. These results suggest that peritonitis is associated with the upregulation of TGF-βl, a mechanism that may exacerbate adhesion formation.

Colonic metaplasia in the ileal pouch is associated with inflammation and is not the result of long-term adaptation.

Ileal pouch-anal anastomosis (IPAA) is the preferred surgical therapy for chronic ulcerative colitis (CUC) and familial adenomatous polyposis (FAP). Previous studies have demonstrated morphologic changes in pouch mucosa such as villous atrophy and crypt hyperplasia. These changes have been labeled “colonic metaplasia.” The aims of this study were to determine whether these changes represent “normal” long-term adaptation of the nondiseased pouch or instead are present only in the setting of inflammation. Twenty-four patients were identified, greater than 5 years status post-IPAA for CUC, who underwent pouchoscopy for surveillance and had no history of pouchitis. Thirty-one patients were identified greater than 5 years status post-IPAA for CUC, who had a history of pouchitis and had undergone pouchoscopy at least 5 years status post-IPAA. Eight patients status post-IPAA for FAP were also identified. Biopsy specimens were reevaluated by a single, blinded pathologist for degree of inflammation, the presence of villous atrophy and crypt hyperplasia, and evidence of dysplasia. Among the patients with CUC, the inflammation score was greater in the pouchitis group, 13.2 ± 1.2, compared to the nonpouchitis group, 4.0 ± 0.5 (P< 0.0001). Median colonic metaplasia score was greater in the pouchitis group (4 [range 2 to 6]) vs. 2 (9 [range 0 to 6]; P <0.0001). The colonic metaplasia score correlated with the inflammation score (Spearman coefficient r = 0.83; P<0.0001). In the eight patients with FAP, the inflammation score was 5.1 ± 0.9 and the median colonic metaplasia score was 1 (range 0 to 4). There was no evidence of dysplasia in any of the biopsy specimens. Patients without a history of pouchitis or symptoms of pouchitis have only a minimal degree of villous atrophy and crypt hyperplasia. These morphologic changes in the ileal pouch are found primarily in the setting of inflammation, and likely represent a reparative response.