Downregulation of CX3CR1 ameliorates experimental colitis: evidence for CX3CL1-CX3CR1-mediated immune cell recruitment.

PURPOSE: Inflammatory conditions like inflammatory bowel diseases (IBD) are characterized by increased immune cell infiltration. The chemokine ligand CX3CL1 and its receptor CX3CR1 have been shown to be involved in leukocyte adhesion, transendothelial recruitment, and chemotaxis. Therefore, the objective of this study was to describe CX3CL1-CX3CR1-mediated signaling in the induction of immune cell recruitment during experimental murine colitis. METHODS: Acute colitis was induced by dextran sodium sulfate (DSS), and sepsis was induced by injection of lipopolysaccharide (LPS). Serum concentrations of CX3CR1 and CX3CL1 were measured by ELISA. Wild-type and CX3CR1-/- mice were challenged with DSS, and on day 6, intravital microscopy was performed to monitor colonic leukocyte and platelet recruitment. Intestinal inflammation was assessed by disease activity, histopathology, and neutrophil infiltration. RESULTS: CX3CR1 was upregulated in DSS colitis and LPS-induced sepsis. CX3CR1-/- mice were protected from disease severity and intestinal injury in DSS colitis, and CX3CR1 deficiency resulted in reduced rolling of leukocytes and platelets. CONCLUSIONS: In the present study, we provide evidence for a crucial role of CX3CL1-CX3CR1 in experimental colitis, in particular for intestinal leukocyte recruitment during murine colitis. Our findings suggest that CX3CR1 blockade represents a potential therapeutic strategy for treatment of IBD.

Tissue factor: a mediator of inflammatory cell recruitment, tissue injury, and thrombus formation in experimental colitis.

There is growing evidence for an interplay between inflammatory and coagulation pathways in acute and chronic inflammatory diseases. However, it remains unclear whether components of the coagulation pathway, such as tissue factor (TF), contribute to intestinal inflammation, and whether targeting TF will blunt the inflammatory cell recruitment, tissue injury, and enhanced thrombus formation that occur in experimental colitis. Mice were fed 3% dextran sodium sulfate (DSS) to induce colonic inflammation, with some mice receiving a mouse TF-blocking antibody (muTF-Ab). The adhesion of leukocytes and platelets in colonic venules, light/dye-induced thrombus formation in cremaster muscle microvessels, as well as disease activity index, thrombin-antithrombin (TAT) complexes in plasma, and histopathologic changes in the colonic mucosa were monitored in untreated and muTF-Ab-treated colitic mice. In untreated mice, DSS elicited the recruitment of adherent leukocytes and platelets in colonic venules, caused gross and histologic injury, increased plasma TAT complexes, and enhanced thrombus formation in muscle arterioles. muTF-Ab prevented elevation in TAT complexes, reduced blood cell recruitment and tissue injury, and blunted thrombus formation in DSS colitic mice. These findings implicate TF in intestinal inflammation and support an interaction between inflammation and coagulation in experimental colitis.

Impact of failed allograft nephrectomy on initial function and graft survival after kidney retransplantation.

The management of an asymptomatic failed renal graft remains controversial. The aim of our study was to explore the effect of failed allograft nephrectomy on kidney retransplantation by comparing the outcome of recipients who underwent graft nephrectomy prior to retransplantation with those who did not. Retrospective comparison of patients undergoing kidney retransplantation with (group A, n = 121) and without (group B, n = 45) preliminary nephrectomy was performed, including subgroup analysis with reference to patients with multiple (≥2) retransplantations and patients of the European Senior Program (ESP). Nephrectomy leads to increased panel reactive antibody (PRA) levels prior to retransplantation and is associated with significantly increased rates of primary nonfunction (PNF; P = 0.05) and acute rejection (P = 0.04). Overall graft survival after retransplantation was significantly worse in group A compared with group B (P = 0.03). Among the subgroups especially ESP patients showed a shorter graft survival after previous allograft nephrectomy. On the multivariate analysis, pretransplant graft nephrectomy and PRA >70% were independent and significant risk factors associated with graft loss after kidney retransplantation. Nephrectomy of the failed allograft was not beneficial for retransplant outcome in our series. Patients with failed graft nephrectomy tended to have a higher risk of PNF and acute rejection after retransplantation. The possibility that the graft nephrectomy has a negative impact on graft function and survival after retransplantation is worth studying further.

Endothelial caveolin-1 regulates pathologic angiogenesis in a mouse model of colitis.

BACKGROUND & AIMS: Increased vascular density has been associated with progression of human inflammatory bowel diseases (IBDs) and animal models of colitis. Pathologic angiogenesis in chronically inflamed tissues is mediated by several factors that are regulated at specialized lipid rafts known as caveolae. Caveolin-1 (Cav-1), the major structural protein of caveolae in endothelial cells, is involved in the regulation of angiogenesis, so we investigated its role in experimental colitis. METHODS: Colitis was induced by administration of dextran sodium sulfate to wild-type and Cav-1(-/-) mice, as well as Cav-1(-/-) mice that overexpress Cav-1 only in the endothelium. Colon tissues were analyzed by histologic analyses. Leukocyte recruitment was analyzed by intravital microscopy; angiogenesis was evaluated by immunohistochemistry and in vivo disk assays. RESULTS: Cav-1 protein levels increased after the induction of colitis in wild-type mice. In Cav-1(-/-) mice or mice given a Cav-1 inhibitory peptide, the colitis histopathology scores, vascular densities, and levels of inflammatory infiltrates decreased significantly compared with controls. Lower levels of leukocyte and platelet rolling and adhesion colitis also were observed in Cav-1(-/-) mice and mice given a Cav-1 inhibitory peptide, compared with controls. Cav-1(-/-) mice that received transplants of wild-type bone marrow had a lower colitis score than wild-type mice. Data from mice that overexpress Cav-1 only in the endothelium indicated that endothelial Cav-1 is the critical regulator of colitis. Genetic deletion or pharmacologic inhibition of endothelial Cav-1 also significantly decreased vascular densities and angiogenesis scores, compared with controls. CONCLUSIONS: Endothelial Cav-1 mediates angiogenesis in experimental colitis. Modulation of Cav-1 could provide a novel therapeutic target for IBD.

Challenges in pancreatic adenocarcinoma surgery - National survey and current practice guidelines.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most deadly cancers in Europe and the USA. There is consensus that radical tumor surgery is the only viable option for any long-term survival in patients with PDAC. So far, limited data are available regarding the routine surgical management of patients with advanced PDAC in the light of surgical guidelines. METHODS: A national survey on perioperative management of patients with PDAC and currently applied criteria on their tumor resectability in German university and community hospitals was carried out. RESULTS: With a response rate of 81.6% (231/283) a total of 95 (41.1%) participating departments practicing pancreatic surgery in Germany are certified as competence and reference centers for surgical diseases of the pancreas in 2016. More than 95% of them indicate to carry out structured and interdisciplinary therapies along with an interdisciplinary pre- and postoperative tumor board. The majority of survey respondents prefer the pylorus-preserving partial pancreatoduodenectomy (93.1%) with standard lymphadenectomy for cancer of the pancreatic head. Intraoperative histological evaluation of the resection margins is used regularly by 99% of the survey respondents. 98.7% of survey respondents carry out partial or complete vein resection, 126 respondents (54.5%) would resect tumor adjacent arteries, and 102 respondents (44.2%) would perform metastasectomy if complete PDAC resection (R0) is possible. CONCLUSION: Evidence-based and standardized pancreatic surgery is practiced by a large number of hospitals in Germany. However, a significant number of survey respondents support an extended radical tumor resection in patients with advanced PDAC even when not indicated by current clinical guidelines.

Cytomegalovirus Treatment Strategy After a Liver Transplant: Preemptive Therapy or Prophylaxis for Cytomegalovirus Seropositive Donor and Recipient.

OBJECTIVES: Cytomegalovirus infections cause the most frequent infection after solid-organ transplant. While Cytomegalovirus prophylaxis is established in high-risk patients (donor+/ recipient-), data on Cytomegalovirus prophylaxis in other serostatus constellation are rare. The aim of this study was to evaluate the influence of Cytomegalovirus treatment strategy after a liver transplant (preemptive therapy vs general prophylaxis) in the largest group of patients: Cytomegalovirus seropositive donor and recipient. MATERIALS AND METHODS: Forty-seven seropositive recipients of seropositive donor liver transplants (D+/R+, 2005-2012) were included in this retrospective study. Twenty-one patients received oral valganciclovir as Cytomegalovirus prophylaxis 100 days after transplant. Cytomegalovirus infection and Cytomegalovirus disease were monitored during the first 6 months. RESULTS: A Cytomegalovirus infection could be detected in 4 out of 47 patients (8.5%), including Cytomegalovirus disease in 2 patients (Cytomegalovirus pneumonia and Cytomegalovirus-CNS disease). Three of these patients received no Cytomegalovirus prophylaxis (P = .408). Eight patients developed a graft failure; this occurred more frequently among patients without Cytomegalovirus prophylaxis (P = .044). Patients receiving Cytomegalovirus prophylaxis more often developed leukopenia. No difference was seen regarding the number of platelets, hemoglobin, and creatinine. CONCLUSIONS: Cytomegalovirus prophylaxis can minimize the risk of Cytomegalovirus reactivation and graft failure. However, disadvantages of the prophylaxis as leukopenia should be considered.

Tacrolimus Concentration/Dose Ratio is Associated with Renal Function After Liver Transplantation.

BACKGROUND: The calcineurin inhibitor (CNI) tacrolimus (Tac) is an effective immunosuppressant used after liver transplantation (LTx), but is often associated with CNI nephrotoxicity. Currently, there is no simple clinical predictor for CNI nephrotoxicity after LTx. We hypothesized that the Tac metabolism rate - defined as the blood concentration normalized by its daily dose (the C/D ratio) - is associated with post-LTx renal impairment. MATERIAL AND METHODS: We analyzed the relationship between the C/D ratio and post-transplant renal function in 179 patients who underwent LTx between 2000 and 2012 and were initially immunosuppressed with Tac, mycophenolate mofetil, and prednisolone. Six months after LTx, 115 patients were categorized into 1 of 2 groups based on their Tac C/D ratio (<1.09 or ≥1.09): fast (n=58) or slow (n=57) metabolizers. The renal function was determined 36 months after LTx using the estimated glomerular filtration rate (eGFR) as described by Cockcroft and Gault. RESULTS: At the time of LTx there was no statistically significant difference between the eGFR of fast and slow metabolizers. Six months (P=0.016), 12 months (P=0.001), and 36 months (P=0.018) after LTx, fast Tac metabolizers had significantly more impaired renal function than slow metabolizers. Because of a presumption of CNI nephrotoxicity, 32.8% of fast metabolizers and 14.0% of slow metabolizers were switched from Tac to other immunosuppressants (P=0.027). CONCLUSIONS: In this study, the Tac metabolism rate appears to influence renal function after LTx, suggesting that a C/D ratio of <1.09 is associated with increased CNI nephrotoxicity in LTx recipients.

Submucosal collecting venules: a reliable site for intestinal intravital microscopy in rats.

Under physiological conditions and after interventions such as ischemia/reperfusion, postcapillary mesenteric venules are most commonly used for in vivo assessment of intestinal microcirculation by intravital microscopy (IVM). In experimental models of gut inflammation, however, IVM was found to be hampered by postinflammatory tissue injury. In this study, postcapillary submucosal collecting venules located at the junction of mesentery and ileum are introduced and evaluated for IVM in a rat model of indomethacin-induced ileitis. The injection of indomethacin was followed by a significant increase in the number of sticking and rolling leukocytes. At the submucosal localization, rollers increased from 5.9 +/- 1.4/0.01 mm(2)/30 s to 34.8 +/- 13.4/0.01 mm(2)/30 s (p <.05), and at the mesentery from 8.0 +/- 2.1/0.01 mm(2)/30 s to 43.1 +/- 13.5/0.01 mm(2)/30 s (p <.05). The number of adherent leukocytes measured at the submucosal level went from 0.21 +/- 0.2/0.01 mm(2)/30 s up to 10.9 +/- 2.9/0.01 mm(2)/30 s (p <.05) and at the mesentery from 0.16 +/- 0.2/0.01 mm(2)/30 s to 15.4 +/- 3.4/0.01 mm(2)/30 s (p <.05). The macroscopic ranking showed an ulcer index of 4.93 +/- 0.76 in the indomethacin group versus 0 in the control group. We found that, despite severe inflammation, this site provided easy and reliable access for IVM. Therefore, we suggest this submucosal site for future studies of intestinal microcirculation in rat models of gut inflammation.

Prognostic factors for kidney allograft survival in the Eurotransplant Senior Program.

BACKGROUND: The shortage of organ donors has led to the introduction of the Eurotransplant Senior Program (ESP) to optimize the allocation of kidneys from elderly donors by age-matching. In the face of a rapidly aging population, identification of prognostic factors for kidney allograft survival within the ESP population will be of enormous significance. MATERIAL AND METHODS: Donor and recipient data from 89 patients transplanted under the ESP protocol between 1999 and 2007 were retrospectively analyzed. Data were correlated with initial graft function, graft survival, acute rejection episodes, serum creatinine levels, glomerular filtration rates, and patient survival using univariate and multivariate analysis. Maximum follow-up was 5 years. RESULTS: Cold ischemia time (CIT) >16 hours, body mass index (BMI) ≥25 kg/m(2), and kidney re-transplantation were significant risk factors for delayed graft function (DGF). Odds ratio for primary non-function was significantly increased with prolonged CIT, BMI ≥25 kg/m(2), and duration of renal replacement therapy >69 months. CIT >15 h, DGF, and kidney re-transplantation were associated with poor graft survival (P<0.05). CONCLUSIONS: Risk reduction (e.g., aiming at CIT <15 h) and close surveillance of patients at risk appear to be crucial for allograft survival in the ESP.

Small bowel transplantation complicated by cytomegalovirus tissue invasive disease without viremia.

We report on a small bowel transplant patient, donor/recipient seropositive (D+/R+) for cytomegalovirus (CMV), with a clinical course complicated by CMV disease. Anti-CMV prophylaxis was given for 100 days. Immunosuppression consisted of alemtuzumab, tacrolimus, mycophenolate mofetil and prednisolone. Five months posttransplant, CMV tissue invasive disease of the upper gastrointestinal tract was evident without the presence of viremia, tested by quantitative polymerase chain reaction (PCR). Complete viral load suppression was achieved with intravenous ganciclovir, followed by valganciclovir for secondary prophylaxis. Mycophenolate mofetil and prednisolone were discontinued. Shortly thereafter the patient presented with recurrent CMV and candida esophagitis. While on ganciclovir and caspofungin, the patient developed CMV tissue invasive disease of the ileal graft, with persistent absence of viremia. Foscarnet and CMV immunoglobulin were added. Viral load declined to undetectable levels; however, clinical improvement did not occur due to occurrence of graft rejection. Despite infliximab and high dose prednisolone, graft rejection was progressive, requiring surgical explantation of the graft. This case highlights the importance of additional diagnostic tools such as endoscopy including PCR analysis of tissue samples. Extension of primary antiviral prophylaxis interval up to 6 months and prolonged retreatment for recurrent CMV disease may be useful to avoid severe CMV-related complications.

Intestinal cancer risk in Crohn's disease: a meta-analysis.

AIM OF THE STUDY: To clarify the intestinal cancer risk in Crohn's disease (CD). METHODS: 20 clinical studies (1965-2008) with a total of 40,547 patients with Crohn's disease-associated cancer (CDAC) were included in the meta-analysis ("inverse variance weighted" method). RESULTS: The incidence of CDAC in any CD patient was 0.8/1,000 person years duration (pyd) (CI, 0.6-1.0). The incidences of different carcinomas were: colorectal cancer 0.5/1,000 pyd (CI, 0.3-0.6), small bowel carcinoma 0.3/1,000 pyd (CI, 0.1-0.5), and cancers arising from CD-associated fistulae 0.2/1,000 pyd (CI, 0.0-0.4). Compared to the incidence in an age-matched standard population, the risk of colorectal cancer was increased by factor 2-3 and of small bowel cancer by factor 18.75, respectively. Mean patient age at diagnosis of CD-associated colorectal cancer was 51.5 years, thus 20 years earlier than in a standard population. The mean duration of CD until diagnosis of CDAC was 18.3 years. Duration of CD, age at diagnosis of CD, and anatomical area of CD involvement had no significant influence on cancer incidence. CONCLUSIONS: CD is a risk factor for colorectal cancer, small bowel cancer, and fistula cancer; however, compared to ulcerative colitis, cancer risk is moderate.

Role of LPS in the hepatic microvascular dysfunction elicited by cecal ligation and puncture in mice.

BACKGROUND/AIMS: Sepsis remains a leading cause of death in critically ill patients. Because endotoxemia is viewed as a key mediator of sepsis-induced inflammation, administration of bacterial endotoxin (LPS) is often used to simulate sepsis in experimental animals. This study tests the hypothesis that LPS is a critical determinant of the hepatic microvascular dysfunction in mice made septic by cecal ligation and puncture (CLP). METHODS: Intravital videomicroscopy was used to quantify sinusoidal perfusion, and platelet and leukocyte adhesion in terminal hepatic venules (THV) and sinusoids in LPS-sensitive and LPS-insensitive mice subjected to CLP or LPS (i.p.). mRNA expression of TLR-2, TLR-4, MyD-88, and Ly-96 was also assessed. RESULTS: While LPS-sensitive mice responded to both CLP and LPS challenges with elevated leukocyte and platelet adhesion in THV and sinusoids, and a reduced sinusoidal perfusion density, LPS-insensitive mice exhibited comparable blood cell adhesion and sinusoidal malperfusion following CLP, but not LPS. Hepatic mRNA of MyD-88 and TLR-2 was elevated in the CLP and LPS groups. Endotoxin was not detectable in the blood of LPS-sensitive mice after CLP, but was elevated after LPS administration. CONCLUSIONS: These findings do not support a major role for LPS in the hepatic microvascular disturbances associated with polymicrobial sepsis.

Mechanisms of platelet and leukocyte recruitment in experimental colitis.

Both leukocytes and platelets accumulate in the colonic microvasculature during experimental colitis, leading to microvascular dysfunction and tissue injury. The objective of this study was to determine whether the recruitment of leukocytes and platelets in inflamed colonic venules are codependent processes. The rolling and adherence of leukocytes and platelets in colonic venules of mice with dextran sodium sulfate (DSS)-induced colitis were monitored by intravital videomicroscopy. DSS elicited an increased recruitment of both rolling and adherent leukocytes and platelets. DSS-colitic mice rendered thrombocytopenic with anti-platelet serum exhibited profound reductions in leukocyte adhesion. Neutropenia, induced with anti-neutrophil serum, significantly reduced the adhesion of leukocytes and the accumulation of platelet-leukocyte aggregates while greatly enhancing the number of platelets that roll and adhere directly to venular endothelial cells. The enhanced platelet adhesion associated with neutropenia was mediated by platelet P-selectin interactions with endothelial cell P-selectin glycoprotein ligand (PSGL-1). DSS colitis was also associated with an increased expression of PSGL-1 in the colonic vasculature. These findings indicate that the recruitment of leukocytes and platelets in inflamed colonic venules are co-dependent processes.

Role of blood- and tissue-associated inducible nitric-oxide synthase in colonic inflammation.

There is evidence that inducible nitric-oxide synthase (iNOS)-derived NO contributes to the pathophysiology of intestinal inflammation. The aims of this study were to assess the role of iNOS in the development of dextran sodium sulfate (DSS)-induced colonic inflammation and to define the contribution of tissue-specific iNOS expression to this inflammatory response. Study groups included: 1) wild-type (WT) mice; 2) WT=>WT bone marrow chimeras with normal iNOS function; 3) WT=>iNOS-/- chimeras (with functional blood cell iNOS, but iNOS-deficient tissue); 4) iNOS-/-=>WT chimeras (with iNOS-deficient blood cells, but normal tissue iNOS activity); and 5) iNOS-deficient mice. In WT mice and WT=>WT chimeras, DSS-induced colonic inflammation was characterized by bloody diarrhea and a high disease activity index. However, WT=>iNOS-/- and iNOS-/-=>WT chimeras and iNOS-/- mice exhibited an attenuated disease activity index, with parallel changes in histopathology. Colonic myeloperoxidase (MPO) was comparably elevated in DSS-treated WT mice (30.1+/-1.7) and WT=>WT chimeras (29.0+/-1), whereas MPO was significantly reduced in iNOS-/- mice and iNOS-/-=>WT chimeras (9.5+/-1.7 and 15.6+/-2.2, respectively). WT=>iNOS-/- chimeras exhibited the lowest MPO activity (3.7+/-0.6). Our findings implicate both blood cell- and tissue-derived iNOS in DSS-induced colonic inflammation, with tissue-associated iNOS making a larger contribution to the recruitment of inflammatory cells.

CD40-CD40 ligand mediates the recruitment of leukocytes and platelets in the inflamed murine colon.

BACKGROUND AND AIMS: Although the CD40-CD40 ligand (CD40L) signaling pathway has been implicated in the pathogenesis of a variety of diseases, including inflammatory bowel disease, the nature of its contribution to intestinal inflammation remains poorly understood. The aim of this study was to determine whether CD40-CD40L contributes to the intestinal inflammatory response, tissue injury, and disease activity elicited by dextran sodium sulphate (DSS) through the modulation of leukocyte and platelet recruitment in the colonic microvasculature. METHODS: Wild-type (WT), CD40(-/-), and CD40L(-/-) mice were fed DSS drinking water. On day 6, intravital videomicroscopy was performed to monitor leukocyte and platelet recruitment in colonic venules, with measurements obtained for tissue myeloperoxidase and histology. CD40 expression on colonic endothelium was measured using the dual-radiolabeled antibody technique. RESULTS: A comparison of the responses to DSS-induced colitis in CD40(-/-) and CD40L(-/-) mice to WT mice revealed a significant attenuation of disease activity and histologic damage, as well as profound reductions in the recruitment of adherent leukocytes and platelets in the mutant mice. Similar down-regulation of the blood cell recruitment responses to DSS was noted in WT mice treated with the CD40-CD40L pathway inhibitor Trapidil. CD40 expression in the colonic vasculature was greatly elevated during DSS-induced inflammation in WT mice, but not in CD40(-/-) mice. CONCLUSIONS: These findings implicate CD40-CD40L in the pathogenesis of DSS-induced intestinal inflammation, and suggest that modulation of leukocyte and platelet recruitment by activated, CD40-positive endothelial cells in colonic venules may represent a major action of this signaling pathway.

PECAM-1 (CD 31) mediates transendothelial leukocyte migration in experimental colitis.

Transendothelial migration of circulating leukocytes into the colonic wall is a key step in the development of the inflammatory infiltrate in inflammatory bowel disease (IBD). The platelet-endothelial cell adhesion molecule-1 PECAM-1 (CD31) is expressed in the tight junction area of endothelial cells, where it is supposed to support the transmigration process. The aim of this study was to determine the role of PECAM-1 in experimental IBD and to show whether blockade of PECAM-1 has therapeutic effects. Chronic colitis was induced in female BALB/c mice by cyclic oral administration of dextran sodium sulfate (DSS) 3% (wt/vol). Expression of PECAM-1 was visualized by immunohistochemistry. In the treatment group animals received 1 mg/kg anti-PECAM-1 (2H8) ip daily starting on day 26. On day 30 leukocyte adhesion and migration was measured during N(2)O-isoflurane anesthesia in the distal colon by intravital microscopy. Disease activity index (DAI), histology, and MPO levels were compared with healthy and diseased controls. PECAM-1 was expressed in colitic mice. Chronic DSS colitis was characterized by a marked increase in rolling, adherent, and transmigrated leukocytes compared with healthy controls. Immunoblockade of PECAM-1 reduced leukocyte transmigration significantly and also diminished leukocyte rolling and sticking in an indirect manner. It also resulted in a significantly diminished DAI and MPO levels, as well as an amelioration of the histological inflammation score. PECAM-1 plays an important role in transendothelial leukocyte migration in DSS colitis. PECAM-1 could be a novel target for antibody-based treatment in IBD.

Bosentan, an endothelin receptor antagonist, reduces leucocyte adhesion and inflammation in a murine model of inflammatory bowel disease.

BACKGROUND AND AIMS: Endothelins, a group of polyfunctional cytokines, induce the adhesion of circulating leucocytes to venous endothelium, an initial step in the pathogenesis of a cellular infiltrate in inflammatory bowel disease (IBD). The effect of bosentan, a non-selective endothelin receptor antagonist, on leucocyte adhesion and inflammation in a murine model of IBD was studied. MATERIALS AND METHODS: Thirty BALB/c mice were divided into three groups of 10 animals: untreated controls, chronic colitis [dextran sodium sulphate (DSS), 3% w/v for 30 days], and treatment with bosentan (30 mg/kg i.p. daily on days 26-30). On day 30, adherent and rolling leucocytes and the average rolling velocity were assessed by intravital microscopy. Clinical and histological activity of inflammation were assessed by the disease activity index and modified Dieleman score, respectively. STATISTICS: Kruskal-Wallis test was used, followed by Dunn's method. A value of p<0.05 was considered significant. RESULTS: Compared to healthy controls, mice treated with DSS showed pronounced clinical and histological inflammation, and a higher number of rolling and adhering leucocytes in colonic submucosal venules. Therapy with bosentan significantly reduced clinical and histological inflammation. Adherent leucocyte levels were markedly lower (1.2+/-0.3 vs 23.7+/-2.8 adherent cells per 0.01 mm2, p<0.05). The number of rolling leucocytes was lower but not significantly different. However, rolling velocity was significantly higher (91.5+/-14.0 vs 19.0+/-1.6 microm/s, p<0.05). CONCLUSIONS: Bosentan reduces the adhesion of leucocytes in colonic submucosal venules and reduces inflammation in this mouse model of IBD. By inhibiting leucocyte adhesion, a crucial step in the recruitment of leucocytes to the inflamed tissue, bosentan is a potent therapeutic drug in this animal model. Further studies are necessary to investigate the role of bosentan as a novel drug in human IBD.

Preoperative steroid administration: effect on morbidity among patients undergoing intestinal bowel resection for Crohns disease.

Long-term steroid therapy may predispose to increased perioperative morbidity in patients undergoing surgery with bowel anastomoses. The aim of our study was to review our data to determine if the steroid dosage is associated with the incidence of early complications after bowel resection in patients with prolonged steroid therapy for Crohns disease (CD). Altogether, 397 patients underwent bowel resection with primary intestinal anastomoses for CD between 1982 and 2000 in our institution. The mortality and morbidity rates, anastomotic leakage, wound infections, intraabdominal abscesses, reoperation rate, and length of postoperative hospitalization in patients who were having high-dose (>/= 20 mg of prednisolone per day, n = 73) and low-dose (< 20 mg prednisolone per day, n = 146) steroid therapy for more than 1 month before surgery were compared with those of patients ( n = 177) who were not receiving steroids. Statistical analysis was performed using Fisher's exact test and Student's t-test, with p < 0.05 considered significant. The three groups were similar in terms of gender, duration since first diagnosis, American Society of Anesthesiologists classification, and obesity. Mortality, morbidity, anastomotic leakage, wound infections, intraabdominal abscesses, reoperation rate, and average postoperative stay were not statistically different in patients with high-dose, low-dose, or no steroid therapy. The only factor associated with increased morbidity was a low preoperative hemoglobin level. Our results demonstrate that, in patients who are undergoing bowel resection for CD, even high-dose prolonged preoperative systemic steroid therapy is not associated with increased postoperative complications.

Is colonoscopy alone sufficient to screen for ulcerative colitis-associated colorectal carcinoma?

Patients with ulcerative colitis (UC) are at increased risk for colorectal carcinoma (CAC). Despite the fact that patients at risk are followed closely by colonoscopy to screen for dysplasia, the prevalence of CAC is still unacceptably high. The aim of this study was to evaluate the prevalence of risk factors for CAC, such as dysplasia, and to determine the relevance of colonoscopic surveillance in the group who went on to develop cancer. A series of 24 patients with UC were diagnosed with CAC. The patients' records were analyzed retrospectively for duration of UC, prevalence of preoperative dysplasia, and other cancer risk factors (CRFs) (e.g., pancolitis, primary sclerosing cholangitis, early onset of UC, and backwash ileitis). The mean age of the patients at the time of cancer diagnosis was 43 years with an average UC duration of 15 years (6 patients had had UC less than 8 years). CAC was identified preoperatively by colonoscopy in 15 of 24 patients, with an additional 7 of 15 showing flat dysplasia. Five of nine patients without preoperatively diagnosed CAC had flat dysplasia. Overall, 19 patients had additional CRFs, most of them with at least two more CRFs. Despite a regular colonoscopic follow-up for most patients with UC, flat dysplasia was missed in 12 patients preoperatively. Therefore we suggest that patient information should also always include surgical options in each case where significant cancer risk factors are found.