Walter A. Koltun

CD1d-expressing Dendritic Cells but Not Thymic Epithelial Cells Can Mediate Negative Selection of NKT Cells

Natural killer T (NKT) cells are a unique immunoregulatory T cell population that is positively selected by CD1d-expressing thymocytes. Previous studies have shown that NKT cells exhibit autoreactivity, which raises the question of whether they are subject to negative selection. Here, we report that the addition of agonist glycolipid α-galactosylceramide (α-GalCer) to a fetal thymic organ culture (FTOC) induces a dose-dependent disappearance of NKT cells, suggesting that NKT cells are susceptible to negative selection. Overexpression of CD1d in transgenic (Tg) mice results in reduced numbers of NKT cells, and the residual NKT cells in CD1d-Tg mice exhibit both an altered Vβ usage and a reduced sensitivity to antigen. Furthermore, bone marrow (BM) chimeras between Tg and WT mice reveal that CD1d-expressing BM-derived dendritic cells, but not thymic epithelial cells, mediate the efficient negative selection of NKT cells. Thus, our data suggest that NKT cells developmentally undergo negative selection when engaged by high-avidity antigen or abundant self-antigen.

Gentamicin-collagen sponge for infection prophylaxis in colorectal surgery

BACKGROUND Despite the routine use of prophylactic systemic antibiotics, surgical-site infection continues to be associated with significant morbidity and cost after colorectal surgery. The gentamicin-collagen sponge, an implantable topical antibiotic agent, is approved for surgical implantation in 54 countries. Since 1985, more than 1 million patients have been treated with the sponges. METHODS In a phase 3 trial, we randomly assigned 602 patients undergoing open or laparoscopically assisted colorectal surgery at 39 U.S. sites to undergo either the insertion of two gentamicin-collagen sponges above the fascia at the time of surgical closure (the sponge group) or no intervention (the control group). All patients received standard care, including prophylactic systemic antibiotics. The primary end point was surgical-site infection occurring within 60 days after surgery, as adjudicated by a clinical-events classification committee that was unaware of the study-group assignments. RESULTS The incidence of surgical-site infection was higher in the sponge group (90 of 300 patients [30.0%]) than in the control group (63 of 302 patients [20.9%], P=0.01). Superficial surgical-site infection occurred in 20.3% of patients in the sponge group and 13.6% of patients in the control group (P=0.03), and deep surgical-site infection in 8.3% and 6.0% (P=0.26), respectively. Patients in the sponge group were more likely to visit an emergency room or surgeons office owing to a wound-related sign or symptom (19.7%, vs. 11.0% in the control group; P=0.004) and to be rehospitalized for surgical-site infection (7.0% vs. 4.3%, P=0.15). The frequency of adverse events did not differ significantly between the two groups. CONCLUSIONS Our large, multicenter trial shows that the gentamicin-collagen sponge is not effective at preventing surgical-site infection in patients who undergo colorectal surgery; paradoxically, it appears to result in significantly more surgical-site infections. (Funded by Innocoll Technologies; ClinicalTrials.gov number, NCT00600925.)

Remicade does not abolish the need for surgery in fistulizing Crohn's disease.

AbstractPURPOSE: Tumor necrosis factor antagonist therapy in the form of infliximab has been shown to promote significant healing in fistulizing Crohn’s disease and therefore is often considered as a possible alternative to surgery. Our aim was to evaluate the role of infliximab in supplanting surgery for fistulizing Crohn’s disease. METHODS: We performed a retrospective chart review of all adult patients who received infliximab for fistulizing Crohn’s disease at one institution between September 1998 and October 2000. RESULTS: Twenty-six patients (14 male; mean age, 38 years; range, 19–80 years) received a mean of three (range, one to six) doses of infliximab (5 mg/kg) with the intent to cure fistulizing Crohn’s disease. Nine patients (35 percent) had perianal, 6 (23 percent) enterocutaneous, 3 (12 percent) rectovaginal, 4 (15 percent) peristomal, and 4 (15 percent) intra-abdominal fistulas. Nineteen (73 percent) of the patients had had prior surgery for Crohn’ s disease. Six patients (23 percent) had a complete response to infliximab with fistula closure, 12 (46 percent) had a partial response, and 8 (31 percent) had no response to infliximab. Fourteen (54 percent) patients still required surgery for their fistulizing Crohn’s disease after infliximab therapy (10 bowel resections, 4 perianal procedures), whereas half (6/12) of the patients treated with infliximab who still had open fistulas after treatment declined surgical intervention. Five of six patients with fistula closure on infliximab had perianal or rectovaginal fistulas. None of the patients with either enterocutaneous or peristomal fistulas were healed with infliximab. CONCLUSIONS: Although it was associated with a 61 percent complete or partial response rate, infliximab therapy did not supplant the need for surgical intervention in the majority of our patients with fistulizing Crohn’s disease. Seventy-three percent of the patients either required surgery or still had open fistulas after infliximab therapy. Infliximab was much more effective in treating perianal disease than abdominal enterocutaneous disease.

Dehydration Is the Most Common Indication for Readmission After Diverting Ileostomy Creation

BACKGROUND: Early readmission after discharge from the hospital is an undesirable outcome. Ileostomies are commonly used to prevent symptomatic anastomotic complications in colorectal resections. OBJECTIVE: The aim of this study was to identify factors predictive of readmission after colectomy/proctectomy and diverting loop ileostomy. DESIGN: This study is a retrospective review. PATIENTS: Patients were included who underwent colon and rectal resections with ileostomy at our institution. Sex, age, type of disease, comorbidities, elective vs urgent procedure, type of ileostomy, operative method, steroid use, ASA score, and the use of diuretics were evaluated as potential factors for readmission. MAIN OUTCOME MEASURES: The primary outcomes measured were the need for readmission and the presence of dehydration (ostomy output ≥1500 mL over 24 hours and a blood urea nitrogen/creatinine level ≥20, or physical findings of dehydration). RESULTS: Six hundred three loop ileostomies were created mostly in white (95.3%), male (55.6%) patients undergoing colon or rectal resections. IBD was the most common indication at 50.9%, with rectal cancer at 16.1%, and other at 31.0%. The 60-day readmission rate was 16.9% (n = 102) with the most common cause dehydration (n = 44, 43.1%). Regression analysis demonstrated that the laparoscopic approach (p = 0.02), lack of epidural anesthesia (p = 0.004), preoperative use of steroids (p = 0.04), and postoperative use of diuretics (p = 0.0001) were highly predictive for readmission. Furthermore, regression analysis for readmission for dehydration identified the use of postoperative diuretics as the sole risk factor (p = 0.0001). LIMITATIONS: This study is limited by the retrospective analysis of data, and it does not capture patients that were treated at home or in clinic. CONCLUSION: Readmission after colon or rectal resection with diverting loop ileostomy was high at 16.9%. Dehydration was the major cause for readmission. Patients receiving diuretics are at increased risk for readmission for dehydration. High-risk patients should be treated more cautiously as inpatients and closely monitored in the outpatient setting to help reduce dehydration and readmission.

Indeterminate colitis predisposes to perineal complications after ileal pouch-anal anastomosis.

This study retrospectively evaluated 288 patients who had undergone ileal pouch-anal anastomosis to determine the incidence of perineal complications and to relate these findings to the pathologic diagnosis, with the goal of specifically clarifying the appropriate surgical management of patients with indeterminate colitis. Of these 288 patients, 235 patients (82 percent) had a diagnosis of chronic ulcerative colitis, 18 patients (6 percent) had indeterminate colitis, 6 patients (2 percent) had Crohns disease, and 29 patients (10 percent) had familial polyposis. All complications occurred at least 6 months after closure of the stoma and required operative therapy. Of 18 patients with indeterminate colitis, 9 patients experienced complications (50 percent)vs.8 of 235 patients with chronic ulcerative colitis (3 percent), a highly significant difference (P<0.001). Furthermore, the risk of eventual ileostomy because of perineal complications was 0.4 percent in patients with chronic ulcerative colitisvs.28 percent in patients with indeterminate colitis (P<0.001). We conclude that a diagnosis of indeterminate colitis predisposes the patient undergoing ileal pouchanal anastomosis to perineal complications, with a resultant high chance of reservoir loss. Ileal pouch-anal anastomosis should be considered with caution in the patient with a diagnosis of indeterminate colitis.

Awake epidural anesthesia is associated with improved natural killer cell cytotoxicity and a reduced stress response

BACKGROUND Laparotomy under general anesthesia is associated with depressed natural killer cell cytotoxicity (NKCC) and compromised clearance of tumor cells. We tested the hypothesis that awake epidural anesthesia (AEA) improves NKCC compared to conventional general endotracheal anesthesia (GEA). PATIENTS AND METHODS Preoperative, perioperative, and postoperative (day 3) NKCC, plasma epinephrine, norepinephrine, cortisol levels, and 24-hour urinary cortisol levels were measured in 20 patients undergoing open colectomy under either AEA or GEA. RESULTS Preoperative and postoperative measurements were not significantly different in the two groups. Patients receiving GEA had a significant reduction in NKCC from 36% +/- 4% preoperatively to 22% +/- 4% perioperatively (P = 0.02). Patients receiving AEA had no significant change in NKCC. Perioperative plasma epinephrine and cortisol levels were higher with GEA than AEA. The perioperative 24-hour urinary cortisol excretion values were significantly higher in the group receiving GEA, suggesting a greater stress hormone response in this group compared to AEA patients. CONCLUSIONS Compared to GEA, AEA appears to preserve perioperative NKCC. This effect may be related to an attenuated stress hormone response associated with AEA. Cancer patients may have improved killing of embolized tumor cells during surgery performed under AEA.

Tumor necrosis factor alpha disrupts tight junction assembly

BACKGROUND We have previously shown an increase in intestinal permeability and a corresponding decrease in the expression of tight junction (TJ) proteins in the in testines of patients with Crohns disease (CD). Tumor necrosis factor-alpha (TNFalpha) has been implicated in the inflammatory process of CD and its suppression has therapeutic benefit. ZO-1, occludin, and the claudins are key proteins in the TJ. HYPOTHESIS TNFalpha disrupts the TJ. METHODS MDCK cells were incubated with TNFalpha (0-100 ng/ml) for 5 days. Qualitative evaluation of the TJ was done with monoclonal antibody to ZO-1 detected by an immunofluorescence. Duplicate cells were lysed and ZO-1, occludin, and claudin-1 amount determined by western blot. RESULTS Immunofluorescent staining of MDCK cells for ZO-1 showed TJ structural disruption with increasing amount of TNFalpha characterized by fragmented staining of ZO-1. There were no significant differences in quantitation of ZO-1 or occludin in the MDCK cells for all TNFalpha concentrations. There was a significant decrease in the amount of claudin-1 with increasing concentration of TNFalpha. CONCLUSIONS (1) MDCK TJs are qualitatively disrupted by TNFalpha. (2) This disruption is not because of a decrease in cell number, lack of cell layer confluency, or a decrease in the amount of ZO-1 or occludin. (3) The amount of claudin-1 present in the cell is decreased with increasing amounts of TNFalpha suggesting that the lack of claudin-1 may cause a relocation of ZO-1 away from the TJ. (4) This rearrangement may play a role in the increased intestinal permeability seen in CD and other diseases.

Identification of disease-associated DNA methylation in intestinal tissues from patients with inflammatory bowel disease

Lin Z, Hegarty JP, Cappel JA, Yu W, Chen X, Faber P, Wang Y, Kelly AA, Poritz LS, Peterson BZ, Schreiber S, Fan J‐B, Koltun WA. Identification of disease‐associated DNA methylation in intestinal tissues from patients with inflammatory bowel disease.

Factors affecting surgical risk in elderly patients with inflammatory bowel disease

The operative treatment of elderly patients with inflammatory bowel disease (IBD) has often been avoided in favor of medical management because of a perceived increase in surgical risk. This study sought to define the following in the elderly IBD patient population: (1) the risk of surgical management and (2) those factors affecting risk. Thirty patients with IBD, aged 60 years or more, who were surgically managed by a single surgeon over a 10-year period, were retrospectively matched to 75 patients with IBD who were less than 60 years of age; patients were matched according to sex, date of surgery, and type of surgery performed. Regression analysis using generalized estimating equation methodology to account for the matched clusters of patients was performed to evaluate the effect of age group on the complication rate, operating room time, and length of hospital stay. Presence of comorbid conditions, surgical indications, prior surgery for IBD, and the use of immunosuppressive medications were studied in multivariate models, adjusting for age group. By means of univariate analysis, the odds of complications in elderly IBD patients were shown to be statistically higher than the odds seen in younger patients (47% vs. 20%, P= 0.01). Also observed in the elderly group were a longer length of hospital stay (11.5 days vs. 7.1 days, P = 0.001) and longer operating room time (249 minutes vs. 212 minutes, P= 0.02). Multivariate analysis revealed that the effect of age remained statistically significant, even when adjusted for potential confounding variables such as comorbidity, medications, date of diagnosis of IBD, and indications for surgery. The complication outcome was significantly associated with the surgical indication, with obstruction, fistula, and bleeding having increased odds of complications as compared with other indications (odds ratio = 1.7 vs. 4.2 vs. 7.2, respectively, P= 0.02). The length of hospital stay similarly was significantly associated with the surgical indication (fistula, 10.5 days vs. bleeding, 9.8 days vs. obstruction, 7.4 days vs. other, 9.3 days; P= 0.04) and a history of prior surgery. A significant interaction for length of hospital stay was present between age group and prior surgery status (with prior surgery: old, 18 days vs. young, 6.4 days, P= 0.0001; without prior surgery: old, 9.5 days vs. young 7.3 days, P= 0.10). Elderly patients with IBD have an increased rate of postoperative complications along with an increased length of hospital stay and increased operating room time. This effect of age persists when adjusted for comorbidity and immuno-suppressive therapy. Complications are most dependent on surgical indications, with obstruction being the least and bleeding the worst predictive factors. The longest hospital stay is associated with patients who require surgery for fistulous disease and patients who have undergone previous surgery. The fact that the higher complication rate seen in older patients with IBD is associated with disease-defined surgical indications suggests that IBD in elderly patients may be more aggressive than what is observed in younger individuals.

The NOD2insC polymorphism is associated with worse outcome following ileal pouch-anal anastomosis for ulcerative colitis

Background Inflammatory complications after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) are common. Objective To investigate whether genetic factors are associated with adverse pouch outcomes such as chronic pouchitis (CP) and a Crohns disease-like (CDL) phenotype. Design 866 patients were recruited from three centres in North America: Mount Sinai Hospital (Toronto, Ontario, Canada), the Cleveland Clinic (Cleveland, Ohio, USA) and Penn State Milton S Hershey Medical Center (Hershey, Pennsylvania, USA). DNA and clinical and demographic information were collected. Subjects were classified into post-surgical outcome groups: no chronic pouchitis (NCP), CP and CDL phenotype. Results Clinical and genetic data were available on 714 individuals. 487 (68.2%) were classified as NCP, 118 (16.5%) CP and 109 (15.3%) CDL. The presence of arthritis or arthropathy (p=0.02), primary sclerosing cholangitis (p=0.009) and duration of time from ileostomy closure to recruitment (p=0.001) were significantly associated with outcome. The NOD2insC (rs2066847) risk variant was the single nucleotide polymorphism (SNP) most significantly associated with pouch outcome (p=7.4×10−5). Specifically, it was associated with both CP and CDL in comparison with NCP (OR=3.2 and 4.3, respectively). Additionally, SNPs in NOX3 (rs6557421, rs12661812), DAGLB (rs836518) and NCF4 (rs8137602) were shown to be associated with pouch outcome with slightly weaker effects. A multivariable risk model combining previously identified clinical (smoking status, family history of inflammatory bowel disease), serological (anti-Saccharomyces cerevisiae antibody IgG, perinuclear antineutrophil cytoplasmic antibody and anti-CBir1) and genetic markers was constructed and resulted in an OR of 2.72 (p=8.89×10−7) for NCP versus CP/CDL and 3.22 (p=4.11×10−8) for NCP versus CDL, respectively. Conclusion Genetic polymorphisms, in particular, the NOD2insC risk allele, are associated with chronic inflammatory pouch outcomes among patients with UC and IPAA.