Influence of the inclination angle of the S1 pedicle on screw malposition and operative revision in percutaneous iliosacral screw fixation of posterior pelvic ring fractures.

INTRODUCTION: Due to aging society, osteoporotic posterior ring fractures of the pelvis are gaining importance. Percutaneous iliosacral screw fixation can reduce pain if conservative therapy is not sufficient. One of the surgical complications is the malposition of the screws in neuroforamen. The aim of this study is to correlate the measured pedicle angle with the screw position in postoperative CT scans. MATERIALS AND METHODS: In this retrospective study (level of evidence: III), 97 patients with posterior ring fractures were treated with 137 percutaneous iliosacral screws. The inclination angles of the S1 pedicle were measured in the preoperative pelvic CT scan of each patient. Patients were divided up into pedicle angles from 10 - 19.9° (Group 1), 20 - 29.9° (Group 2), 30 - 39.9° (Group 3) and 40 - 49.9° (Group 4). We correlated the pedicle inclination angle to radiologically described screw position in the L5/S1 neuroforamen and the need for revision because of screw malposition. RESULTS: A total of 10 pedicle inclination angles were from 10 - 19.9° (7.3%), 96 from 20 - 29.9° (70.1%), 28 from 30 - 39.9° (20.4%) and three from 40 - 49.9° (2.2%). Of the 137 screws used, 19 were intraforaminal (13.9%). There were no intraforaminal screws in the Group 1, eight in Group 2, 10 in Group 3 and one in Group 4. Five of the screws needed revision (3,6%). There were no revisions in Groups 1 and 4, two in Group 2 and three in Group 3. Groups 3 and 4 had a higher percentage of intraforaminal screw positions. Patients with steeper angles S1 pedicles showed a significantly higher probability of intraforaminal screw location and revision (p<0.01). DISCUSSION: Complications such as intraforaminal screw position and revision surgery are more frequent in patients with steeper S1 pedicles, making this a detrimental prognostic marker.

A new device to prevent fascial retraction in the open abdomen - proof of concept in vivo.

BACKGROUND: An open abdomen is often necessary for survival of patients after peritonitis, compartment syndrome, or in damage control surgery. However, abdominal wall retraction relieves delays and complicates abdominal wall closure. The principle of the newly fascia preserving device (FPD) is the application of anteriorly directed traction on both fascial edges over an external support through a longitudinal beam to relieve increased abdominal pressure and prevent fascial retraction. METHODS: Twelve pigs were randomly divided into two groups. Both groups underwent midline laparotomy under general anesthesia. Group one was treated with the new device, group two served as controls. The tension for closing the abdominal fascia was measured immediately after laparotomy as well as at 24 and 48 h. Vital parameters and ventilation pressure were recorded. Post mortem, all fascial tissues were histologically examined. RESULTS: All pigs demonstrated increases in abdominal circumference. In both groups, forces for closing the abdomen increased over the observation period. Concerning the central closing force after 24 h we saw a significant lower force in the FPD group (14.4 ± 3 N) vs. control group (21.6 ± 5.7 N, p < 0.001). By testing the main effects using an ANOVA analysis we found a significant group related effect concerning closing force and abdominal circumference of the FDP-group vs. control group (p < 0.001; p < 0.001). The placement of the device on chest and pelvis did not influence vital parameters and ventilation pressure. Histologic exam detected no tissue damage. CONCLUSIONS: This trial shows the feasibility to prevent fascial retraction during the open abdomen by using the new device. Thus, it is expected that an earlier closure of the abdominal wall will be possible, and a higher rate of primary closure will be attained.

Percutaneous iliosacral screw fixation after osteoporotic posterior ring fractures of the pelvis reduces pain significantly in elderly patients.

INTRODUCTION: Osteoporotic posterior ring fractures of the pelvis are common injuries in the elderly, but the treatment of these fractures still remains controversial. Percutaneous iliosacral screw fixation is one surgical option if conservative treatment cannot provide sufficient pain reduction. The aim of this study is to provide short-term results of elderly patients with percutaneous screw fixation. METHODS: 30 patients with posterior ring fractures were treated between 12/2009 and 01/2014 with percutaneous iliosacral screw fixation. Patients' mean age was 78.4 years. Concerning short-term outcome, we focused on initial pain level and postoperative pain reduction together with intra- and postoperative complications. RESULTS: The average hospital stay was 23.7 days, with surgical treatment performed after an average of 9.2 days. 90% of our patients were female. All 30 patients had a lower level of pain at discharge compared with admission or immediately prior to surgery. The difference in pain level at admission compared with the pain level upon discharge showed a mean reduction from 6.8 to 1.8 with a statistically significant change (P≤0.001). 24 of 30 patients had no registered complications, one screw malpositioning with postoperative nerve irritation occurred. DISCUSSION: Conventional percutaneous iliosacral screw fixation is a successful operative treatment for elderly patients with persistent lower back pain after unstable posterior ring fractures of the pelvis. Intra- and postoperative complications are rare, so this treatment can be regarded as a safe procedure. LEVEL OF EVIDENCE: IV (retrospective study).

Treatment of unstable elbow dislocations with hinged elbow fixation-subjective and objective results.

BACKGROUND: The aim of this study was to provide subjective and objective results of surgical treatment of unstable elbow dislocations with the hinged external fixation technique. METHODS: Twenty-six patients were available for re-examination after treatment. Parameters used to quantify the subjective functional results were the Mayo Elbow Performance Score, the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire, and the stability of the elbow joint. In addition, we measured the medial and lateral joint space by varus and valgus stress ultrasound examinations of the elbow. RESULTS: The mean Mayo Elbow Performance Score was 93.5 (±8.3 standard deviation), and the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire showed an average of 7.3 points (±8.9 standard deviation). We saw 18 patients with stable joints and 8 patients with slight instability. In the ultrasound stress test, we saw a significant difference of the affected joint under varus stress (7.8 ± 1.7 mm) compared with the healthy joint (5.8 ± 1.2 mm) laterally. Furthermore, medially the gap was significantly larger (4.8 ± 0.9 mm; treated elbow) than contralaterally under valgus stress (3.3 ± 0.7 mm) (P < .001). CONCLUSION: Closed reduction and hinged external fixation of unstable elbow dislocations resulted in good and very good results. We could identify a slight difference in the stability of the affected elbow compared with the contralateral side in all patients without clinical relevance.

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.

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.

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.

Efficient activation of autologous tumor-specific T cells: a simple coculture technique of autologous dendritic cells compared to established cell fusion strategies in primary human colorectal carcinoma.

Different technologies have been employed to deliver the whole spectrum of tumor antigens (TAs) to dendritic cells (DCs) to be presented to T cells. These include whole tumor RNA-transfected DCs, preparations of DCs loaded with tumor-derived apoptotic bodies or tumor cell lysates, and DC tumor cell fusions. Early clinical trials have been conducted using such techniques. The presented study was aimed to revisit the necessity of tumor cell manipulation in DC-based immunotherapy strategies for colorectal carcinoma. We investigated a simple coculture method of autologous monocyte-derived DCs and human primary colorectal carcinoma (pCC) in comparison with 2 well-described cell fusion strategies for the efficacy of uptake, processing and presentation of TAs to autologous T cells. Before coculture or fusion, pCC had been cryopreserved without further manipulation. Fluorescence microscopy and flow cytometry analyses of fluorescent dye labeled cells were used for monitoring engulfment of pCC by DCs. The coculture procedure resulted in a double positive cell fraction of up to 22% and thus was comparable to that observed after cell fusion. More important, DCs after coculture with autologous pCC induced significant tumor-specific interferon-gamma-producing autologous T cells in the same number of patients as DC/pCC fusions. Furthermore, tumor-specific major histocompatibility complex class I restricted cytotoxic T lymphocytes were generated by stimulation with DCs cocultured with pCC. In prior studies for human carcinomas coculture techniques were described to be inferior. In contrast, our data strongly suggest that at least for human pCC and autologous DCs this simple coculture method is similarly efficient compared to established fusion techniques.

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.

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.

Intestinal cancer in patients with Crohn's disease.

BACKGROUND: Surveillance of intestinal cancer in Crohn's disease (CD) has often been advocated. To date, no clear evidence exists whether CD patients are at special risk for intestinal cancer. An increased incidence of small bowel adenocarcinoma is suggested. However, recent figures also suggest an increased risk of CD associated colorectal cancer. We report our experience with 10 cases of CD complicated by intestinal adenocarcinoma. MATERIALS AND METHODS: Our institutional database included 330 patients treated for CD between 1988-2005. Data of patients that developed carcinoma within Crohn's lesions of either small or large bowel were analyzed. RESULTS: Ten patients were diagnosed with CD complicated by carcinoma. In nine patients, cancer was present in the colorectum and in one, in Crohn's ileitis. Tumors were in conjunction with fistulae in three and developed within strictures in five patients. Mean age at the time of diagnosis of CD was 43 years. Mean duration of CD until diagnosis of cancer was 14 years. Only five patients were diagnosed for cancer preoperatively. Staging revealed advanced tumors in almost all patients. Mean survival after surgery was 29 months (2-149 months). CONCLUSIONS: Cancer risk in CD and especially in Crohn's colitis may still be underestimated. Delayed diagnosis resulted in a poor prognosis. The value of colonoscopy as surveillance tool is questioned by the fact that in our patients, carcinoma was diagnosed in some patients preoperatively by routine colonoscopy. Therefore, additional markers should be identified to detect CD patients at risk.

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.

Expression of vascular cell adhesion molecule-1 (CD 106) in normal and neoplastic human esophageal squamous epithelium.

Vascular cell adhesion molecule-1 (VCAM-1), a key receptor for the leukocyte-associated integrin (VLA4), is a crucial mediator of leukocyte adhesion and has co-stimulatory functions in inflammation at various organ sites. Specifically, VCAM-1/VLA4 interactions have been shown to play important roles in the setting of cutaneous immune responses, such as psoriatic lesions in humans and acute Graft-versus-Host-Disease in mice. VCAM-1 is generally expressed on activated endothelial cells in inflamed tissues, mediating endothelium-leukocyte interactions, leading to leukocyte diapedesis to the site of inflammation. We report novel and unexpected membrane expression of VCAM-1 in the basal squamous epithelial strata of the normal human esophagus and distinct patterns of epithelial expression in esophageal pathology. To further delineate the differential expression patterns of VCAM-1 in the esophageal epithelium, we examined specimens from squamous cell carcinoma (SCC), adenocarcinoma, and Barrett's columnar cell metaplasia. VCAM-1 was strongly expressed in squamous cell carcinoma, but not adenocarcinoma nor columnar epithelia in Barrett's esophagus. VCAM-1 expression was focally accentuated at sites characteristic of microscopic tumor invasion in SCC, pointing to a potential role of VCAM-1 in the development of metastasis. In addition, in vitro immunofluorescence studies using OE21 cells, an esophageal squamous epithelial cell line, displayed distinct VCAM-1 immunoreactivity confined to mitotic and dividing cells. Cell cycle arrest caused a significant decrease in VCAM-1 immunoreactivity in OE21 cells. These data suggest a previously unappreciated role for VCAM-1 in esophageal squamous epithelial homeostasis and pathology.

Differential expression and regulation of murine CD40 in regional vascular beds.

There is emerging evidence for a role of the CD40/CD40 ligand (CD40L) dyad as a signaling mechanism in different inflammatory conditions. The aims of this study were to 1) quantify the constitutive and induced expression of CD40 in different regional vascular beds of the mouse and 2) assess the role of CD40L as a modulator of vascular endothelial CD40 expression. The dual radiolabeled monoclonal antibody technique was used to quantify the expression of endothelial CD40 in control and LPS-challenged wild-type (WT) mice. Significant constitutive CD40 expression was detected in several vascular beds of WT mice with lung, kidney, and small intestine exhibiting the highest expression, whereas the liver and stomach showed no detectable baseline expression. LPS administration elicited two- to sevenfold increases in CD40 expression in several tissues (heart, kidney, and intestine) within 4 h, whereas other organs (brain) required up to 48 h to exhibit CD40 upregulation. CD40 expression was not detected in unstimulated or LPS-challenged CD40-/- mice. Constitutive expression of CD40 was profoundly reduced in unstimulated CD40L-/- mice, but the LPS-induced CD40 upregulation did not differ between CD40L-/- and WT mice. Depletion of platelets or T lymphocytes, the major CD40L-expressing cells in blood, also resulted in a profound reduction in basal CD40 expression. These findings demonstrate significant endothelial expression of CD40 under basal conditions in different vascular beds and increased CD40 expression after endothelial cell activation with LPS. Platelet- and T-lymphocyte-associated CD40L appears to play a major role in regulating the density of CD40 expression on vascular endothelial cells in vivo.

"Pancreatic lesion" outside the pancreas: value of endoscopic ultrasound.

Tumors of the small intestine are rare as compared to malignant tumors of the pancreas. Here we report on the case of a 61-year-old man suffering from chronic pancreatitis presenting with a lesion projecting into the pancreatic head shown by both computed tomography and transabdominal ultrasound. Pancreatic cancer was suspected, but endoscopic ultrasound revealed this lesion to be situated in the submucosal layer of the duodenal wall. Surgery was performed since biopsy of this lesion was not diagnostic and a malignant leiomyosarcoma could therefore not be excluded. Limited surgery comprised resection of the duodenal lesion, whereas based on computed tomography alone, exploration of the pancreas would have been performed. Thus, in the present case endoscopic ultrasound leads to a more appropriate, less invasive therapeutic measure.

Molecular determinants of the prothrombogenic phenotype assumed by inflamed colonic venules.

Although platelets have been implicated in the pathogenesis of human inflammatory bowel diseases, little is known about the magnitude of platelet accumulation in the inflamed bowel, what regulates this process, and its relevance to the overall inflammatory response. In this study, intravital video microscopy was used to monitor the trafficking of platelets and leukocytes and vascular permeability in colonic venules during the development of colonic inflammation induced by 3% dextran sodium sulfate (DSS). Blocking antibodies directed against different adhesion molecules as well as P-selectin-deficient mice were used to define the adhesive determinants of DSS-induced platelet recruitment. DSS induced an accumulation of adherent platelets that was temporally correlated with the appearance of adherent leukocytes and with disease severity. Platelet adhesion and, to a lesser extent, leukocyte adhesion were attenuated by immunoblockade of P-selectin and its ligand P-selectin glycoprotein ligand-1 (PSGL-1), with contributions from both platelet- and endothelial cell-associated P-selectin. DSS induced a rapid and sustained increase in vascular permeability that was greatly attenuated in P-selectin-deficient mice. P-selectin bone marrow chimeras revealed that both endothelial cell- and platelet-associated P-selectin contribute to the P-selectin expression detected in the inflamed colonic microvasculature, with endothelial P-selectin making a larger contribution. Our findings indicate that colonic inflammation is associated with the induction of a prothrombogenic phenotype in the colonic microcirculation, with P-selectin and its ligand PSGL-1 playing a major role in the recruitment of platelets.

Antigen transport and cytoskeletal characteristics of a distinct enterocyte population in inflammatory bowel diseases.

Intestinal antigen uptake is enhanced in inflammatory bowel disease. We analyzed transcellular transport routes of antigens in different compartments of normal enterocytes and atypical intestinal epithelial cells called "rapid antigen uptake into the cytosol enterocytes" (RACE cells). These cells constitute a recently described population of enterocyte-derived cells, which are increased in inflammatory bowel disease. Mucosa of freshly resected specimens were incubated with the antigens ovalbumin or horseradish peroxidase. Ultrastructural labeling patterns of differentiation-dependent proteins, the brush-border enzyme sucrase-isomaltase and the cytoskeleton proteins villin and actin, were determined in enterocytes. Apoptosis was investigated biochemically and ultrastructurally by cleavage of caspase-3. Both antigens were transported to late endosomes and to trans-Golgi vesicles of enterocytes in inflammatory bowel disease and control specimens. Quantitative evaluation revealed a significantly increased transepithelial antigen transport in both compartments of RACE relative to normal enterocytes. Labeling densities for sucrase-isomaltase, villin, and actin were decreased in RACE relative to normal enterocytes. Caspase-3 was not increased in RACE cells relative to controls. RACE cells are characterized by increased antigen transport to late endosomes and the trans-Golgi network, a disassembled cytoskeleton and lower concentrations of proteins that are markers of cell differentiation.

Apolipoprotein A-IV inhibits experimental colitis.

The antiatherogenic properties of apoA-IV suggest that this protein may act as an anti-inflammatory agent. We examined this possibility in a mouse model of acute colitis. Mice consumed 3% dextran sulfate sodium (DSS) in their drinking water for 7 days, with or without daily intraperitoneal injections of recombinant human apoA-IV. apoA-IV significantly and specifically delayed the onset, and reduced the severity and extent of, DSS-induced inflammation, as assessed by clinical disease activity score, macroscopic appearance and histology of the colon, and tissue myeloperoxidase activity. Intravital fluorescence microscopy of colonic microvasculature revealed that apoA-IV significantly inhibited DSS-induced leukocyte and platelet adhesive interactions. Furthermore, apoA-IV dramatically reduced the upregulation of P-selectin on colonic endothelium during DSS-colitis. apoA-IV knockout mice exhibited a significantly greater inflammatory response to DSS than did their WT littermates; this greater susceptibility to DSS-induced inflammation was reversed upon exogenous administration of apoA-IV to knockout mice. These results provide the first direct support for the hypothesis that apoA-IV is an endogenous anti-inflammatory protein. This anti-inflammatory effect likely involves the inhibition of P-selectin-mediated leukocyte and platelet adhesive interactions.

Impact of dextran sulfate sodium load on the severity of inflammation in experimental colitis.

In dextran sulfate sodium (DSS)-induced inflammatory bowel disease in mice the relationship between the amount of ingested DSS and the severity of colitis has not been systematically investigated. We examined whether (1) the severity of colitis is DSS load-dependent, and (2) there is a critical DSS load required to reliably induce colitis. DSS load was calculated as: (drinking volume (ml) x [DSS (g)/100 ml])/body weight (g). A minimum DSS load > or = 30 mg/g body weight over 7 days resulted in a significantly elevated colonic myeloperoxidase (MPO) activity, compared to mice receiving less DSS and controls (P < 0.05). Histomorphologic data correlated with MPO activity and revealed significantly higher damage scores once the DSS load was > or = 30 mg/g body weight. Our findings demonstrate the importance of monitoring DSS load in this model of experimental colitis.

Immunoblockade of PSGL-1 attenuates established experimental murine colitis by reduction of leukocyte rolling.

Recruitment of circulating leukocytes into the colonic tissue is a key feature of intestinal inflammation. P-selectin glycoprotein ligand-1 (PSGL-1) and very late antigen-4 (VLA-4) are expressed on leukocytes and play an important role in leukocyte-endothelial cell adhesive interactions. We examined the effects of immunoneutralization of PSGL-1 and VLA-4 on leukocyte recruitment in vivo in the development and treatment of experimental colitis. Chronic colitis was induced in balb/c mice by oral administration of dextran sodium sulfate (DSS). Monoclonal antibodies 2PH1 (anti-PSGL-1) and PS/2 (anti-VLA-4) or the combination of both were injected intravenously, and leukocyte adhesion was observed for 60 min in colonic submucosal venules by intravital microscopy (IVM) under isoflurane/N(2)O anesthesia. In addition, mice with established colitis were treated by daily intraperitoneal injections of 2PH1, PS/2, or the combination of both over 5 days. Disease activity index (DAI), histology, and myeloperoxidase (MPO) levels were compared with sham-treated DSS controls. We found that 2PH1 reduced the number of rolling leukocytes (148.7 +/- 29.8 vs. 36.9 +/- 8.7/0.01 mm(2)/30 s, P < 0.05), whereas leukocyte velocity was increased (24.0 +/- 3.6 vs. 127.8 +/- 11.7 microm/s, P < 0.05). PS/2 reduced leukocyte rolling to a lesser extent. Leukocyte firm adhesion was not influenced by 2PH1 but was strongly reduced by PS/2 (24.1 +/- 2 vs. 4.4 +/- 0.9/0.01 mm(2)/30 s, P < 0.05). Combined application did not cause additional effects on leukocyte adhesion. Treatment of chronic colitis with 2PH1 or PS/2 reduced DAI, mucosal injury, and MPO levels significantly. Combined treatment led to a significantly better reduction of DAI (0.4 +/- 0.1 vs. 2.1 +/- 0.2 points) and histology (9.7 +/- 0.9 vs. 21.4 +/- 4.6 points). In conclusion, PSGL-1 and VLA-4 play an important role for leukocyte recruitment during intestinal inflammation. Therapeutic strategies designed to disrupt interactions mediated by PSGL-1 and/or VLA-4 may prove beneficial in treatment of chronic colitis.