Severe Mucosal Injury Research Articles

Patient-reported burden of mucosal injury (MUI): Comparison of clinician-rated MUI and patient-reported outcomes

9117 Background: Patient (pt) reported outcome (PROs) tools identify MUI and its impact on functional and subjective outcomes. Among outpts, PRO tools are attractive because opportunities for direct assessment are limited, but agreement between PRO tools and objective MUI measures has not been uniform. We prospectively compared an objective MUI score and 3 previously validated PRO tools. Method: The Triad Burden of Illness study is an international, 41-center, prospective study of the risk and outcomes of radiation and chemotherapy-induced MUI. At baseline and during chemoradiation therapy (CRT), pts with larynx (L), hypopharynx (H), or non-small cell lung cancers (NSCLC) completed a daily MUI symptom tool (OMDQ) and 2 weekly PRO tools (FACT-E quality of life, FACIT- Fatigue). Clinicians examined pts twice weekly and scored MUI (WHO scale). In this interim analysis, we used random effects linear regression to compare clinician and pt ratings and t-tests to compare PRO scores in pts with and without severe MUI. Result: To date, 29 pts have completed =2 paired assessments; 23 (79%) had L or H cancers. Ulcerative MUI (WHO = 2) was more common among L/H than NSCLC pts (39% vs 17%). Pt-rated MUI predicted clinician-rated MUI (p = 0.001). FACT-E and FACIT-F scores were significantly lower (worse) among pts with clinician-rated ulcerative MUI than pts without and among pts with pt-rated severe MUI symptoms (OMDQ= 2) than pts without. Differences were largest in the subscales for physical and functional wellbeing and esophageal symptom special concerns. Conclusion: PRO tools estimate the burden of CRT-induced MUI in outpts with L/H or NCSL cancers. MUI appears to be associated with significantly poorer quality of life, functional status, and symptom scores. 1- 9 p <0.01; 10p = 0.06. [Table: see text] [Table: see text]

Recognition of Double-Stranded RNA by TLR3 Induces Severe Small Intestinal Injury in Mice

The role of TLRs on intestinal epithelial cells (IECs) is controversial, and the mechanisms by which TLRs influence mucosal homeostasis are obscure. In this study, we report that genomic dsRNA from rotavirus, and its synthetic analog polyinosinic-polycytidylic acid (poly(I:C)), induce severe mucosal injury in the small intestine. Upon engaging TLR3 on IECs, dsRNA triggers IECs to secrete IL-15, which functions to increase the percentage of CD3+NK1.1+ intestinal intraepithelial lymphocytes (IELs) and enhances the cytotoxicity of IELs. Moreover, The CD3+NK1.1+ IELs are proved as CD8alphaalpha+ IELs. These results provide direct evidence that abnormal TLR3 signaling contributes to breaking down mucosal homeostasis and the first evidence of pathogenic effects mediated by CD8alphaalpha+ IELs. The data also suggest that genomic dsRNA may be involved in the pathogenesis of acute rotavirus gastroenteritis.

Intestinal Tight Junction in Allograft After Small Bowel Transplantation

Introduction In the intestinal physical barrier, tight junctions between intestinal epithelial cells play a central role. There is increasing evidence that rejection after small bowel transplantation promotes intestinal barrier injury to allografts. Our aim was to study the morphological changes of tight junctions in allografts during rejection. Methods Small bowel transplantation was performed using the F344 to Lewis rat model. Animals were divided into three groups: isogeneic controls, acute rejection group, and chronic rejection group. Allograft rejection was characterized by hemotoxylin and eosin staining of mucosal tissue sections. Tight junctions in grafts were investigated by transmission electron microscopy. Results Acutely rejected allografts showed severe mucosal injury and completely loosened tight junctions, while chronically rejected allografts revealed less mucosal injury and remained with partial integrity of their tight junctions. Conclusion Our study demonstrated for the first time the morphological alterations of tight junctions in allograft mucosa during acute and chronic rejections, suggesting disruption of tight junctions was relative to the intestinal inflammatory processes.

The Impact of Reflux Composition on Mucosal Injury and Esophageal Function

The components of refluxed gastric juice are known to cause mucosal injury, but their effect on esophageal function is less appreciated. Our aim was to determine the effect of acid and/or bile on mucosal injury and esophageal function. From 1993-2004, 402 patients with reflux symptoms had 24-hour pH and Bilitec monitoring, manometry, and endoscopy with biopsies. Mucosal injury (esophagitis or Barrett's esophagus) and esophageal function (lower esophageal sphincter [LES] characteristics and body contractility) in patients with acid reflux, bile reflux, or both were compared with patients without reflux. Reflux was present in 273/402 patients; of these, 37 (13.5%) had increased exposure to bile, 82 (30.0%) had increased exposure to acid, and 154 (56.4%) had increased exposure to both. Mucosal injury was most common with increased mixed acid and bile exposure, followed by acid alone, and was uncommon with bile alone (P < 0.0001). Functional deterioration paralleled mucosal injury (P < 0.0001). Mixed acid and bile exposure was present in more than half of patients with reflux and was associated with the most severe mucosal injury and the greatest deterioration of esophageal function. This suggests that composition of gastric juice is the primary determinant of inflammatory mucosal injury and subsequent loss of esophageal function.

Randomized Active and Placebo-Controlled Endoscopy Study of a Novel Protected Formulation of Oral Alendronate

Although generally well tolerated, oral aminobisphosphonates have been associated with sporadic cases of severe esophageal injury attributed to pill contact. A novel protected formulation of oral alendronate uses an inert cylindrical shell to prevent mucosal contact with intact tablets. An active and placebo-controlled endoscopy study was undertaken to assess mucosal injury associated with this protected formulation. Healthy volunteers with normal baseline endoscopy were randomly assigned to receive protected alendronate 70 mg/day, standard alendronate 70 mg/day, or placebo for 14 days. Endoscopy was repeated on days 8 and 15. Of 78 subjects, 30 received protected alendronate, 28 received standard alendronate, and 20 received placebo. Mean gastric injury scores did not differ significantly among treatment groups. However, subjects on standard alendronate were more likely than those on protected alendronate to develop severe gastric injury, defined as Lanza score 3 or 4 (67.9% versus 33.3%, P=.009), and more likely to develop a gastric ulcer (21.4% versus 3.3%, P=.015). No differences in symptoms or adverse events were observed. In conclusion, a novel protected formulation of oral alendronate is less likely than standard alendronate to induce severe mucosal injury to the upper gastrointestinal tract.

Luminal preservation of rat small intestine with University of Wisconsin or Celsior solution

Aims Luminal administration of a preservation solution that prevents mucosal injury may decrease posttransplant complications. However, luminal administration of University of Wisconsin solution (UW) is controversial. In this study, we examined the potential of Celsior as a luminal small bowel preservation solution in comparison to UW or UW enriched with glutamine. Methods Small bowels of six normal WagRij rats were excised and divided into six equal segments. Each segment was luminally flushed with 10 mL ice-cold UW, UW with glutamine (20 g/L) or Celsior, and stored for 0, 2.5, and 24 hours at 4°C. LDH, glucose, and lactate concentrations were determined in the preservation solutions. Histologic changes were determined using the Park score. Results Lactate dehydrogenase (LDH) was increased in all solutions after 2.5- and after 24-hour preservation. However, LDH was lower in Celsior than UW and UW with glutamine. Furthermore, higher glucose and lactate levels were found after 2.5- and 24-hour preservation in UW and UW with glutamine compared to Celsior. Histologically, jejunal segments were more susceptible to preservation than ileal segments, irrespective of the preservation solution used. Mucosal injury was evident after 2.5 hours (Park Scale 0–3) and increased significantly after 24 hours (park scale 3–6). Conclusions Based on the lower glucose, lactate, and LDH levels in small intestines stored in Celsior, this study suggests that Celsior is a better luminal preservation solution than UW. Unfortunately, histological evaluations still show severe mucosal injury, indicating that there is a need for better luminal preservation solutions or for concomittant intravascular delivery of a preservation solution.

Probiotics inhibit nuclear factor-κB and induce heat shock proteins in colonic epithelial cells through proteasome inhibition

The extent and severity of mucosal injury in inflammatory bowel diseases are determined by the disequilibrium between 2 opposing processes: reparative and cytoprotective mechanisms vs. inflammation-induced injury. Probiotics may provide clinical benefit by ameliorating colitis; however, their mechanisms of action remain largely unknown. Our objective was to investigate microbial-epithelial interactions that could explain the beneficial therapeutic effects of probiotics. The effect of VSL#3-conditioned media on the nuclear factor-kappaB pathway in young adult mouse colonic epithelial cells was assessed by using monocyte chemoattractant protein-1 enzyme-linked immunosorbent assays; IkappaBalpha, IkappaBbeta, and p105 immunoblot analysis; and nuclear factor-kappaB luciferase reporter gene and proteasome assays. Effects on heat shock proteins were determined by electrophoretic mobility shift assay and immunoblot for heat shock proteins 25 and 72 in young adult mouse colonic cells. Cytoprotection against oxidant injury was determined by chromium 51 release and filamentous and globular actin assays. VSL#3 produces soluble factors that inhibit the chymotrypsin-like activity of the proteasome in gut epithelial cells. Proteasome inhibition is an early event that begins almost immediately after exposure of the epithelial cells to the probiotic-conditioned media. In addition, these bacteria inhibit the proinflammatory nuclear factor-kappaB pathway through a mechanism different from the type III secretory mechanisms described for other nonpathogenic enteric flora. They also induce the expression of cytoprotective heat shock proteins in intestinal epithelial cells. The resulting inhibition of nuclear factor-kappaB and increased expression of heat shock proteins may account for the anti-inflammatory and cytoprotective effects reported for probiotics and may be a novel mechanism of microbial-epithelial interaction. These effects seem to be mediated through the common unifying mechanism of proteasome inhibition.

A clinicopathologic study of isolated intestinal allografts with preformed IgG lymphocytotoxic antibodies

Humoral rejection of human small bowel allografts has not been well documented. The aim of this study was to determine the significance of preformed IgG lymphocytotoxic antibodies, as determined by the modified Amos crossmatch technique, in 6 of 28 (21.4%) adult isolated intestinal allograft recipients treated with tacrolimus basal immunosuppression. The crossmatch with dithiothreitol (DTT) was strongly positive in 5 grafts and weakly positive in the remaining one. The strongly positive crossmatch grafts (n = 5) developed severe mucosal injuries immediately after reperfusion. Within the first 10 days after transplantation, 3 of the 5 strongly positive crossmatch grafts developed clinically and endoscopically documented severe mucosal congestion, cyanotic discoloration, and focal hemorrhage within the allograft. Simultaneous mucosal biopsy specimens demonstrated severe congestion, neutrophilic margination, and fibrin-platelet thrombi within the lamina propria microvasculature, along with focal hemorrhage, but with no histological neutrophilic or necrotizing arteritis, and the immunofluorescent findings were unremarkable. The other 2 strongly positive crossmatch allograft recipients developed macroscopic congestion of mucosa with microscopic foci of congestion and hemorrhage. In contrast, the recipient with a weakly positive crossmatch, as well as the 22 crossmatch negative recipients, exhibited none of these characteristic clinical, endoscopic, or microscopic findings ( P < .05). With prompt augmentation of the immunosuppression therapy, the 3 grafts with the characteristic clinicopathologic syndrome were successfully reversed with the monoclonal antilymphocyte preparation OKT3. Thus there was no statistical difference ( P > .05) in early graft survival and the frequency of acute rejection episodes between the crossmatch-positive and the crossmatch-negative groups within the first 6 months after transplantation. We conclude that preformed IgG lymphocytotoxic antibodies in isolated intestinal recipients can be associated with a characteristic clinicopathologic syndrome during the early postoperative course, similar to that observed in experimental animal models and in other solid organ transplantation. If recognized and treated aggressively, early graft failure can be avoided. The long-term significance of these preformed antibodies has yet to be determined.

A clinicopathologic study of isolated intestinal allografts with preformed lymphocytotoxic antibodies

Humoral rejection of human small bowel allografts has not been well documented. The aim of this study was to determine the significance of preformed IgG lymphocytotoxic antibodies, as determined by the modified Amos crossmatch technique, in 6 of 28 (21.4%) adult isolated intestinal allograft recipients treated with tacrolimus basal immunosuppression. The crossmatch with dithiothreitol (DTT) was strongly positive in 5 grafts and weakly positive in the remaining one. The strongly positive crossmatch grafts (n = 5) developed severe mucosal injuries immediately after reperfusion. Within the first 10 days after transplantation, 3 of the 5 strongly positive crossmatch grafts developed clinically and endoscopically documented severe mucosal congestion, cyanotic discoloration, and focal hemorrhage within the allograft. Simultaneous mucosal biopsy specimens demonstrated severe congestion, neutrophilic margination, and fibrin-platelet thrombi within the lamina propria microvasculature, along with focal hemorrhage, but with no histological neutrophilic or necrotizing arteritis, and the immunofluorescent findings were unremarkable. The other 2 strongly positive crossmatch allograft recipients developed macroscopic congestion of mucosa with microscopic foci of congestion and hemorrhage. In contrast, the recipient with a weakly positive crossmatch, as well as the 22 crossmatch negative recipients, exhibited none of these characteristic clinical, endoscopic, or microscopic findings ( P < .05). With prompt augmentation of the immunosuppression therapy, the 3 grafts with the characteristic clinicopathologic syndrome were successfully reversed with the monoclonal antilymphocyte preparation OKT3. Thus there was no statistical difference ( P > .05) in early graft survival and the frequency of acute rejection episodes between the crossmatch-positive and the crossmatch-negative groups within the first 6 months after transplantation. We conclude that preformed IgG lymphocytotoxic antibodies in isolated intestinal recipients can be associated with a characteristic clinicopathologic syndrome during the early postoperative course, similar to that observed in experimental animal models and in other solid organ transplantation. If recognized and treated aggressively, early graft failure can be avoided. The long-term significance of these preformed antibodies has yet to be determined.

Relationship Between Acute Mucosal Injury, Treatment Efficacy and Esophageal Stricture Following Photodynamic Therapy of Barrett's Esophagus

Background and Objectives: Photodynamic therapy (PDT) may be used as an alternative to esophagectomy for patients with high grade dysplasia (HGD) and/or early cancer in Barrett's esophagus. Endoscopic evaluation of acute mucosal injury is typically performed two days after the treatment. The light dose and severity of mucosal injury are not always well correlated. The objective of this study was to find whether the severity of mucosal injury would be predictive of treatment efficacy and incidence of strictures. Materials and Methods: 113 patients received porfimer sodium (2mg/kg). Three days later, 630 nm light was delivered using a cylindrical diffuser within a 20 mm-diameter PDT balloon. Patients received light doses ranging from 85 J/cm to 115 J/cm. Two days after the treatment, the severity of the mucosal injury was determined endoscopically (4=severe, 3=moderate/severe, 2=mild/moderate, 1=mild, and 0=none). The treatment efficacy (elimination of HGD and/or cancer) was determined by four quadrant biopsies three months after PDT. Stricture formation was determined by incidence of dysphagia and the need for esophageal dilation. 8% of patients had T1 cancers and 92% had HGD. Results: Almost all patients had injury scores of 3 or 4. Esophageal strictures occurred in 7% of patients with an injury score of 3, and in 29% of those with a score of 4. In those with a score of 3, there were 50% of patients with residual cancers (1 of 2 patients). In those with a score of 4, there were no patients with residual cancers (7 of 7). Residual HGD was found in 26% of patients (7 of 27) with a score of 3 and in 23% of patients (19 of 82) with a score of 4. Conclusions: Severe mucosal injury following PDT of Barrett's mucosa is associated with four times higher incidence of strictures compared to that resulting from moderate/severe injury. Severe mucosal injury was necessary for ablation of early cancer in Barrett's mucosa. The incidence of residual HGD was similar regardless of the injury scores (severe vs. moderate/severe).

A Preliminary Report on the Effects of Paclitaxel-Impregnated Stents on Sheep Nasal Mucosa

Traditional frontal sinus stents serve only as mechanical devices. It has been proposed that stents also may serve as drug-delivery systems for the topical application of drugs that minimize postoperative scarring. Paclitaxel (Taxol), which has recognized antiscarring effects, may be incorporated via a polymeric formulation into standard rubber stents. The impact of topically applied paclitaxel on the morphology of the nasal mucosa is unknown. An adult sheep model was used for this study. A modified rubber T-tube stent (incorporating paclitaxel at varying dosages) was secured to each side of the septum in four animals (eight sides). An unmodified T-tube was placed on each side of one animal, a T-tube with the drug carrier (but no paclitaxel) was placed on each side of the second animal, and T-tubes with varying paclitaxel were placed on each side of the final two animals. After 4 weeks, animals were killed and the nasal mucosa was harvested. The nasal mucosa was sectioned and stained with hematoxylin and eosin. A pathologist then assessed the nasal mucosa for vascular congestion, glandular atrophy, chronic inflammation, mucosal metaplasia, and mucosal ulceration. No consistent histopathological differences were noted in the specimens. All specimens showed varying degrees of vascular congestion, glandular atrophy, chronic inflammation, and mucosal metaplasia; the paclitaxel-impregnated stents were not consistently associated with more severe mucosal injury. Finally, mucosal ulceration was noted to be very rare in all specimens. This preliminary report describes the impact of paclitaxel-impregnated stents on sheep nasal mucosa, which tolerated these stents very well. Because paclitaxel minimizes scarring reactions at very low concentrations, paclitaxel-impregnated stents may prove useful in clinical situations in which frontal sinus stenting is deemed necessary. Additional investigations with animal models, as well as clinical trials, may be warranted.

Delayed administration of alpha-melanocyte-stimulating hormone or combined therapy with BAY 11-7085 protects against gut ischemia-reperfusion injury.

Gut ischemia-reperfusion (I/R) injury is a serious complication of shock. Previously we demonstrated that the administration of alpha-melanocyte-stimulating hormone (MSH) immediately before mesenteric I/R protected against postischemic gut injury. In this report, we tested the therapeutic efficacy of alpha-MSH on gut I/R (60 min ischemia, 6 h reperfusion) injury when given at different time points of reperfusion. Rats underwent sham surgery or were treated with saline or with alpha-MSH that was given 1, 2, or 4 h after superior mesenteric artery clamping. Vehicle-treated I/R rats exhibited severe mucosal injury and increased NF-kappaB DNA binding activity, myeloperoxidase (MPO) activity, and interleukin-6 and heme oxygenase-1 (HO-1) expression. In contrast, rats given alpha-MSH at 1 h of reperfusion, but not 2 h or 4 h, exhibited much less mucosal injury. Rats given alpha-MSH at 1 h or 2 h of reperfusion, but not 4 h, exhibited less MPO activity, NF-kappaB DNA binding activity, and interleukin-6 protein and even higher levels of heme oxygenase-1 than vehicle-treated rats. In addition, we found that combined use of alpha-MSH, a known inhibitor of IkappaBalpha tyrosine phosphorylation, with BAY 11-7085, an inhibitor of IkappaBalpha Ser 32,36 phosphorylation, abrogates gut MPO induction and tissue injury at early and late time points of reperfusion. Thus, alpha-MSH, an endogenous peptide with a favorable side-effect profile, is effective in treating experimental gut I/R injury when given early after the initial ischemia and may represent a candidate therapy for gut I/R in humans in whom recognition and treatment are often delayed.

Downregulation of cytoprotective intestinal heat shock proteins in inflamed mucosa and by inflammatory cytokines

Background & Aims: Inducd)/e heat shock proteins (hsp) protect viability, and function of intestinal epithelial cells (IEC) against inflammation-associated injury. Unlike small intestine, they are expressed in coloinc IEC under pfiysiological conditions, an eft~:ct dependent on colonic flora as well as mucosal immune cells Because increased hsp expression in inflamed umcosa would be predicted as a host response to limit the extent and severity of mucosal injury, we invrstigated hsp expression in mucosal biopsies from IBD patients, DSS-induced colitis, and in vitro. Methods: Protein expression of inducfble hsps, hsp25/27 and hsp72, and'the constitutively expressed hsc73 were determined by Western blots and immnnostaining (IH) m colonic tnucosa d-ore 1BD patients and DSS-induced colitis. Proqnflannnatory cytokines IL-1~, TNFoc 1FNy were used to elucidate potential factors ahering hsp expression in murine colon-cells (YAMC) and in vivo. Results: Hsp27 and hsp72, but not hsc73, were significantly decreased (66% and 75% respectively) in areas of active inflammation in IBD patients vs uninvolved or healthy' subject samples. When normalized to two epithelial cell markers (cytokeratm 18 and villin), the decreased expression was highly significant (p<0.01), These changes were paralleled by diminished expression of colonic epithelial cell hsps, assessed by IH. In DSS-induced colitis, a rune-dependent decrease in hsp25 (95%) and hsp72 (53%) protein expression and IH (nadir at day 7) were observed and inversely related to increased myelopenaxidase activuy and histologic grading. By contrast, no changes in mucosal hsc73, villin, or cytokemtin expression were observed. The treatment of YAMC cell lines by I IA~ (5ng/ml) or combined TNFmqFNy (100ng/ml; 200U/relY completely inhibited induced hsp25 and hsp72 expression. In addition, If-l!3 and TNBeFIFNy administered IP to healthy mice resuked in marked depletion of hsp25 (80%) and hsp72 (91%), but not hse73, expression in colon mucosa Conclusion: Expression of cytoprotective hsps, hsp25 and hap72, are decreased in the areas of active inflammation in colon, an effect mediated in part by pro-inflammatory c3aokines, Such an effect would render the colonic mucosa more susceptible to inflammation-associated injury. Conversely, augmentation of the cytopmtective hsp response by pharmacological, dietary, or probiotic treatment could benefit patients with IBD and other conditions of injured mucosa.

Ulcers and Gastritis

This article reviews recently published literature regarding ulcers and gastritis. Although endoscopy is the most useful procedure for diagnosis in the upper gastrointestinal tract, complications do occur, and procedure-related costs are significant. The appropriate indication for endoscopy has recently been debated. Helicobacter pylori is known to be an important pathogen involved in gastric and duodenal inflammation. Peptic ulcer disease and severe gastric mucosal injury are caused by virulent strains, and many reports have focused on CagA. Follow-up studies on surveillance endoscopy in patients with peptic ulcer or gastritis report that patients with atrophic gastritis and intestinal metaplasia are at significantly higher risk for gastric cancer. H. pylori eradication sometimes causes gastroduodenal erosion and reflux esophagitis, and the mechanisms involved have been revealed. Proton-pump inhibitors are useful in the treatment of ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs), reflux esophagitis, and for preventing rebleeding after endoscopic hemostasis, but the effect of long-term acid suppression on the gastric mucosa is still a matter of debate. H. pylori infection and NSAID intake are both risk factors for peptic ulcer disease, and are important aspects in this field.

Effects of NF-kappa B inhibition on mesenteric ischemia-reperfusion injury.

Mesenteric ischemia-reperfusion injury is a serious complication of shock. Because activation of nuclear factor-kappaB (NF-kappaB) has been implicated in this process, we treated rats with vehicle or the IkappaB-alpha inhibitor BAY 11-7085 (25 mg/kg ip) 1 h before mesenteric ischemia-reperfusion (45 min of ischemia followed by reperfusion at 30 min or 6 h) and examined the ileal injury response. Vehicle-treated rats subjected to ischemia-reperfusion exhibited severe mucosal injury, increased myeloperoxidase (MPO) activity, increased expression of interleukin-6 and intercellular adhesion molecule 1 protein, and a biphasic peak of NF-kappaB DNA-binding activity during the 30-min and 6-h reperfusion courses. In contrast, BAY 11-7085-pretreated rats subjected to ischemia-reperfusion exhibited less histological injury and less interleukin-6 and intercellular adhesion molecule 1 protein expression at 30 min of reperfusion but more histological injury at 6 h of reperfusion than vehicle-treated rats subjected to ischemia-reperfusion. Studies with phosphorylation site-specific antibodies demonstrated that IkappaB-alpha phosphorylation at Ser(32),Ser(36) was induced at 30 min of reperfusion, whereas tyrosine phosphorylation of IkappaB-alpha was induced at 6 h of reperfusion. BAY 11-7085 inhibited the former, but not the latter, phosphorylation pathway, whereas alpha-melanocyte-stimulating hormone, which is effective in limiting late ischemia-reperfusion injury to the intestine, inhibited tyrosine phosphorylation of IkappaB-alpha. Thus NF-kappaB appears to play an important role in the generation and resolution of intestinal ischemia-reperfusion injury through different activation pathways.

Rapid lethality of hosts by interleukin-12 following H-2 compatible allogeneic bone marrow transplantation: Reminiscence of gut-associated acute graft-versus-host reaction

T lymphocytes and NK cells play an important role in the graft-versus-host (GVH) disease. IL-12 is known to activate both lymphocyte subpopulations. Here, we examined the effect of IL-12 on the outcome after allogenic bone marrow transplantation (allo-BMT). Experiments were performed in a major histocompatibility complex (MHC)-matched allo-BMT model from DBA/2 to BALB/c mice. We administered IL-12 subcutaneously to recipient BALB/c mice at the day of BMT and 2 days later. At a dose of 200 ng IL-12, mice died between day 4 and day 10. When 50 ng of IL-12 was administered, 50% of the animals died, at a dose of 25 ng all mice recovered. In vivo blocking experiments with antagonistic monoclonal antibodies indicated that the early lethality was mediated by FasL, IFNgamma and TNFalpha. Recognition of third party antigens by donor, but not recipient lymphocytes caused lethality. HE staining of the large intestine of IL-12 treated animals showed a severe mucosal injury associated with infiltrating lymphocytes and apoptotic bodies. In IL-12 treated mice in contrast to untreated control animals, flow cytometry analysis revealed numerous CD3+ T cells and CD11c+ dendritic cells (DC) were found in the large intestine. The interaction of T cells and antigen presenting DC might contribute to the lethality in our system. In light of these findings, the usefulness of IL-12 application for patients after BMT is rather questionable.

Barrett's esophagus

Barrett's esophagus is an acquired condition resulting from severe esophageal mucosal injury. It still remains unclear why some patients with gastroesophageal reflux disease develop Barrett's esophagus whereas others do not. The diagnosis of Barrett's esophagus is established if the squamocolumnar junction is displaced proximal to the gastroesophageal junction and if intestinal metaplasia is detected by biopsy. Despite this seemingly simple definition, diagnostic inconsistencies remain a problem, especially in distinguishing short segment Barrett's esophagus from intestinal metaplasia of the gastric cardia. Barrett's esophagus would be of little importance were it not for its well-recognized association with adenocarcinoma of the esophagus. The incidence of esophageal adenocarcinoma continues to increase and the 5-year survival rate for this cancer remains dismal. However, cancer risk for a given patient with Barrett's esophagus is lower than previously estimated. Current strategies for improved survival in patients with esophageal adenocarcinoma focus on cancer detection at an early and potentially curable stage. This can be accomplished either by screening more patients for Barrett's esophagus or with endoscopic surveillance of patients with known Barrett's esophagus. Current screening and surveillance strategies are inherently expensive and inefficient. New techniques to improve the efficiency of cancer surveillance are evolving rapidly and hold the promise to change clinical practice in the future. Treatment options include aggressive acid suppression, antireflux surgery, chemoprevention, and ablation therapy, but there is still no clear consensus on the optimal treatment for these patients.

NSAID gastric ulceration: predictive value of gastric pH, mucosal density of polymorphonuclear leukocytes, or levels of IL-8 or nitrite.

NSAID use and Helicobacter pylori both cause damage to the gastric mucosa and can cause peptic ulcers. Our aim was to test the relationship between gastric mucosal polymorphonuclear leukocyte (PMN) infiltration and the severity of NSAID-induced gastric injury. H. pylori density, mucosal interleukin-8 (IL-8), and nitrite levels were assessed after receiving placebo and again after receiving 1000 mg of naproxen daily for three days. Histology was graded using a visual analog scale (0-5). IL-8 levels were assayed by ELISA and nitrite levels by Griess reaction. Eleven healthy volunteers with H. pylori infection entered. All had normal-appearing gastric mucosa after placebo. Postnaproxen gastric damage included three with none, one with mild, three with moderate, two with severe, and three were very severe mucosal injury (including one with an ulcer >5 mm). There was an inverse correlation between endoscopic score and the pH of the gastric juice post-therapy (R = -0.77, P = 0.004). There was no significant change in histologic or biochemical parameters from pretreatment levels. And none of the parameters (eg, PMN density) predicted endoscopic outcome. In conclusion, there was no relation between mucosal PMN density and endoscopic mucosa injury. PMN infiltration, while not predictive, may be a surrogate for an H. pylori infection-related increased risk of NSAID ulcers.

Effect of Helicobacter pylori-mediated inflammation on nonsteroidal anti-inflammatory drugs-induced gastric mucosal injury.

Helicobacter pylori (H. pylori) infection and nonsteroidal anti-inflammatory drugs (NSAIDs) are two major causes of gastric ulceration, but relation between H. pylori infection and use of these drugs in gastric mucosal injury is controversial. Neutrophils have been implicated in the pathogenesis of gastric mucosal damage induced by H. pylori or NSAIDs. H. pylori itself and H. pylori extract induce neutrophil activation, such as superoxide production, expression of adhesion molecule (CD11b/CD18) and transendothelial migration, capillary plugging. Several clinical and experimental studies demonstrated that the degree of H. pylori-induced gastric mucosal injury was closely correlated with the extents of H. pylori infection and of neutrophil infiltration, suggesting implication in extravascular neutrophils for H. pylori-induced gastric mucosal injury. On the other hand, aspirin promotes neutrophil-endothelial adhesive interactions via increasing CD11b/CD18, but not neutrophil migration to extravascular space. In addition, our recent in vivo study suggests that neutrophils adhering to the blood vessels, but not neutrophils migrating to the interstitium, are implicated in aspirin-induced gastric mucosal injury. Recently, we found that administration of aspirin to gerbils three weeks after H. pylori inoculation produced severe gastric mucosal injury via marked infiltration of neutrophils. In this animal model, pretreatment with anti-neutrophil serum, elastase inhibitor or scavengers of reactive oxygen species remarkably inhibited gastric mucosal injury. These results suggest that H. pylori infection potentiates aspirin-induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.

Treatment-time-dependence models of early and delayed radiation injury in rat small intestine

Background: The present study modeled data from a large series of experiments originally designed to investigate the influence of time, dose, and fractionation on early and late pathologic endpoints in rat small intestine after localized irradiation. The objective was to obtain satisfactory descriptions of the regenerative response to injury together with the possible relationships between early and late endpoints. Methods: Two- and 26-week pathologic radiation injury data in groups of Sprague–Dawley rats irradiated with 27 different fractionation schedules were modeled using the incomplete repair (IR) version of the linear–quadratic model with or without various time correction models. The following time correction models were tested: (1) No time correction; (2) A simple exponential (SE) regenerative response beginning at an arbitrary time after starting treatment; and (3) A bi-exponential response with its commencement linked to accumulated cellular depletion and fraction size (the ‘intelligent response model’ [INTR]). Goodness of fit of the various models was assessed by correlating the predicted biological effective dose for each dose group with the observed radiation injury score. Results: (1) The incomplete repair model without time correction did not provide a satisfactory description of either the 2- or 26-week data. (2) The models using SE time correction performed better, providing modest descriptions of the data. (3) The INTR model provided reasonable descriptions of both the 2- and 26-week data, confirming a treatment time dependence of both early and late pathological endpoints. (4) The most satisfactory descriptions of the data by the INTR model were obtained when the regenerative response was assumed to cease 2 weeks after irradiation rather than at the end of irradiation. A fraction-size-dependent delay of the regenerative response was also suggested in the best fitting models. (5) Late endpoints were associated with low-fractionation sensitivity and treatment-time dependence even in animal groups that exhibited minimal early mucosal reactions. Conclusion: Radiation injury scores in this rat small intestinal experimental model cannot be adequately described without time correction. ‘Consequential’ mechanisms contribute to the development of late effects, even in animals that do not develop severe early mucosal injuries. The initiation of the regenerative response is subject to a fraction-size-dependent mitotic delay and is linked to the level of accumulated cellular depletion. The response does not cease at the end of therapy but probably continues until maximal healing has taken place.