Crohn's disease and anastomotic recurrence: microvascular ischaemia and anastomotic healing in an animal model

The degree of bowel remission predicts phenotype progression in Crohn's disease

BACKGROUND

Patients with Crohn's disease (CD) are at risk of progressing from inflammatory to stricturing and penetrating phenotypes. The influence of the depth of remission on the risk of progression has not been adequately evaluated.

METHODS

A retrospective cohort study including surgically naïve CD patients with inflammatory phenotype evaluated concomitantly by magnetic resonance enterography and colonoscopy. The degree of remission was correlated with the risk of progressing to stricturing and penetrating phenotypes.

RESULTS

Three hundred nineteen CD patients were included: 27.0% with transmural remission, 16.0% with isolated endoscopic remission, 14.4% with isolated radiologic remission, and 42.6% without remission. Patients with transmural remission presented the lowest rates of phenotype progression (1.2%), with a significant difference compared to isolated radiologic remission (10.9%, p = 0.019), to isolated endoscopic remission (19.6%, p ≤ 0.001), and to no remission (46.3%, p ≤ 0.001). In multivariate regression analysis, transmural remission (OR 0.017 95% CI 0.002-0.135, p < 0.001), isolated radiologic remission (OR 0.139 95% CI 0.049-0.396, p < 0.001), and isolated endoscopic remission (OR 0.301 95% CI 0.123-0.736, p = 0.008) resulted in lower rates of phenotype progression compared to no remission. No patient with transmural or isolated radiologic remission progressed to penetrating phenotypes.

CONCLUSION

The degree of bowel remission correlates with the risk of phenotype progression. Patients with transmural remission are at the lowest risk of progressing to stricturing and penetrating phenotypes.

Anastomotic Techniques for Abdominal Crohn's Disease: Tricks and Tips

After surgical resection for Crohn's disease (CD) endoscopic recurrence is noted within few weeks and almost 80% of patients will have evidence of endoscopic recurrence at the anastomosis after ileocolic resection at 1 year. With time and if left untreated surgical recurrence will be detected at the preanastomotic segment or at the anastomosis in the vast majority of cases. It has become progressively apparent also based on these historical data that anastomotic configuration plays a major role in the subsequent recurrence of CD in surgically induced remission. In this article, we will review the evidence in the literature to support the different anastomotic configurations and we will discuss the principles of surgical prophylaxis of CD recurrence.

Is the degree of i2a recurrence in Crohn's disease secondary to ischemic phenomena?

INTRODUCTION

the Rutgeerts score is used to assess post-surgical recurrence of Crohn's disease (CD). The score initially consisted of four grades, with a subsequent sub-classification of grade 2, under which ulcers confined to the anastomosis (i2a) are considered to be of a probable ischemic origin. The aim of this study was to assess whether ulcers confined to the anastomosis appear at the same frequency in patients undergoing surgery for other causes and can therefore be attributed to post-surgical changes.

MATERIAL AND METHODS

this was a retrospective cohort study with patients who had undergone colonoscopy as per clinical practice between 2017 and 2018. There were two cohorts, one cohort of patients to assess the post-surgical recurrence of CD and another cohort for follow-up after colorectal cancer (CRC) treated with ileocolonic anastomosis.

RESULTS

a total of 185 patients were included; 33 % had undergone surgery for CD and 67 % had undergone surgery for CRC. Fifty-six percent of patients were male. Of the patients in the group with ulcers confined to the anastomosis, 75 % had CD and 25 % had been operated on for CRC; the difference was statistically significant (p < 0.0001). In turn, of the patients operated on for CRC, 95 % had no anastomotic lesions compared to 18 % of patients with CD. These differences reached statistical significance (p < 0.0001).

CONCLUSIONS

In our experience, the occurrence of ulcers on the ileocolonic anastomosis is uncommon in patients that have undergone surgery for CRC, in comparison to patients operated on due to CD. It is possible that these alterations in CD cannot therefore be attributed to solely ischemic or post-surgical phenomena.

Altered pulmonary gas transfer capacity and capillary blood volume in pediatric Crohn's disease

OBJECTIVES

To describe diffusing capacity for carbon monoxide (DLCO) and its components, that is, membrane diffusing capacity (DmCO) and pulmonary capillary blood volume (Vc) in children with Crohn's disease (CD), and to investigate the correlation between these parameters and disease activity.

WORKING HYPOTHESIS

The most common lung function abnormalities are a reduced pulmonary DLCO and small airways disorders which are in many instances, clinically silent. No valid explanations have been proposed regarding the modifications in gas transfer capacity in active CD.

METHODS

DLCO, DmCO, and Vc were measured in 25 CD children by the simultaneous single breath lung diffusing capacity method using nitric oxide (NO) and carbon monoxide (CO) transfer. These parameters were analyzed in relation to the CD disease activity index.

RESULTS

DLCO (90.7 ± 4.5% vs 128.5 ± 4.7%; P < 0.001), Dm (92.4 ± 5.9% vs 125.6 ± 6.3%; P < 0.001), and Vc (72.6 ± 3.7% vs 104.4 ± 4.0%; P < 0.001) were significantly decreased in the active CD group in comparison with the inactive CD group. DLCO (r = -0.60; P < 0.01), DmCO (r = -0.45; P < 0.01), and Vc (r = -0.60; P < 0.01) were inversely correlated to the PCDAI. In 8 patients who participated to the study at initial diagnosis then during remission, DmCO and Vc increased significantly between the active and the inactive period of the disease.

CONCLUSION

Pulmonary diffusing capacity is impaired in children with active CD, mainly because of a decrease of the pulmonary capillary volume.

Coronavirus Infection in Ferrets: Antigen Distribution and Inflammatory Response

Multisystemic granulomatous lesions are the most common finding in ferrets infected by ferret systemic coronavirus (FRSCV). To characterize the inflammatory response developed against this virus, lesions from 4 naturally infected ferrets were examined. Lesions were classified into the 4 known types of granulomas (granulomas without necrosis [G], granulomas with necrosis [G-N], granulomas with neutrophils [G-NL], and diffuse granulomatous inflammation [DG]). The cellular composition of the lesions was characterized on the basis of cellular morphology and immunohistochemistry using markers for T and B-lymphocytes, plasma cells, macrophages, and neutrophils. The extent and distribution of viral antigen expression was also assessed. In G lesions, macrophages were mainly located in the center of the granuloma, with a moderate number of T-lymphocytes scattered among the macrophages, plasma cells, and B-lymphocytes. G-N lesions exhibited a necrotic center surrounded by abundant macrophages, some T-lymphocytes, plasma cells, and a few B-lymphocytes. In G-NL lesions, there was a central area dominated by neutrophils with low numbers of macrophages, plasma cells, and lymphocytes. DG presented similar cell proportions, but distributed evenly throughout the lesions. FRSCV was expressed in G, G-NL, G-N, and DG, with decreasing numbers of immunoreactive cells. This study reveals the important role of macrophages in the inflammatory response of ferrets against the virus and the variable proportions of leukocytes among different types of lesions, indicating their variable age. The results also confirm the similarities of the disease in ferrets to feline infectious peritonitis.

Daikenchuto, a traditional Japanese herbal medicine, for the maintenance of surgically induced remission in patients with Crohn's disease: a retrospective analysis of 258 patients

Purpose

Despite numerous studies, the best postoperative therapy for Crohn’s disease is still undefined. We retrospectively evaluated the effects of postoperative maintenance therapy with daikenchuto, a traditional Japanese Kampo medicine, on the reoperation rate at 3 years in patients with Crohn’s disease.

Methods

A total of 258 patients who underwent surgery for Crohn’s disease were identified for the study. For the prevention of postoperative recurrence, patients were stratified to receive 5-aminosalicylic acid, azathioprine or daikenchuto, and their effects on preventing reoperation at 3 years were evaluated.

Results

Of the 258 patients, 44 required reoperation with intestinal resection within 3 years due to disease recurrence. The 3-year reoperation rate was significantly lower in the postoperative daikenchuto group than in the non-daikenchuto group (11.3 vs. 24.5 %, P = 0.01), and was similarly significantly lower in the postoperative 5-aminosalicylic acid group than in the non-5-aminosalicylic acid group (14.8 vs. 29.6 %, P = 0.0049). A multivariate Cox analysis showed that postoperative daikenchuto (P = 0.035) and postoperative 5-aminosalicylic acid (P = 0.022) were significantly and independently associated with the rate of reoperation at 3 years in patients with Crohn’s disease.

Conclusion

We propose that continuous daikenchuto therapy is a clinically useful and feasible maintenance therapy for the prevention of postoperative reoperation in patients with Crohn’s disease.

TGF-beta1 and IGF-1 and anastomotic recurrence of Crohn's disease after ileo-colonic resection

BACKGROUND

After bowel resection, Crohn's disease (CD) recurs frequently in the site of the anastomosis. Alteration of normal healing processes may play a role in this phenomenon. Transforming growth factor beta (TGF-beta) and insulin-like growth factor (IGF-1) are involved in wound healing mechanisms with pro-fibrogenic properties. The aim of this study was to assess the expression of TGF-beta1 and insulin-like growth factor 1 (IGF-1) in the different zones of the bowel wall to understand why side-to-side anastomosis are associated to a lower recurrence rate compared to end-to-end ones.

PATIENTS AND METHODS

Seventeen patients affected by CD who underwent ileo-colonic resection from 2004 to 2005 were enrolled in this study. Full-thickness tissue samples were obtained from the mesenteric, the lateral, and the anti-mesenteric sides of the macroscopically diseased and healthy ileum for each patient. TGF-beta1 and IGF-1 messenger RNAs (mRNAs) were quantified by real-time polymerase chain reaction. Myeloperoxidase activity and histological disease activity were assessed to quantify the ileal inflammation. Vimentin, desmin, and alpha-smooth muscle actin were stained with immunohistochemistry to assess the fibroblast, smooth muscle cell, and myofibroblasts populations. Comparisons and correlations were carried out with nonparametric tests.

RESULTS

In diseased ileum, TGF-beta1 mRNA transcripts in the antimesenteric side were significantly lower than those of the mesenteric side (p = 0.05), and a significant correlation between TGFbeta-1 levels in diseased bowel and the sampling site was observed (tau = 0.36, p = 0.03). On the contrary, neither the IGF-1 mRNA transcripts nor the distribution of fibroblast, smooth muscle cell, and myofibroblasts populations showed any relation with the sampling site.

CONCLUSION

TGF-beta1 mRNA expression was lower in the anti-mesenteric side of the diseased ileum, and this was consistent with the success of side-to-side anastomosis in preventing CD recurrence. Since high expression of TGF-beta1 was associated to early recurrence, it seems rationale to construct the anastomosis on the anti-mesenteric side of the bowel.

The effects of endothelin receptor blockade by bosentan on the healing of a bowel anastomosis in an experimental Crohn's disease model

OBJECTIVE

It was previously described that endothelins may contribute to the pathogenesis of Crohn's disease. In this study, it was aimed to investigate the effects of endothelin receptor blockade by bosentan on the healing of a bowel anastomosis in an experimental Crohn's disease model.

MATERIAL AND METHODS

Twenty-eight Sprague-Dawley rats were divided into four groups. Groups I and II were used as sham-operated and control groups, respectively. Bowel inflammation induced by intrajejunal injection of iodoacetamide in groups III and IV. Rats in group IV were treated with oral preparation of bosentan 60 mg/kg/day. Three days after induction of the inflammation, partial resection of test loop and anastomosis was performed. Re-laparotomy was performed, anastomosis bursting pressures and peritonitis scores were measured, and tissue samples were obtained for the measurements of tissue hydroxylproline level and mucosal damage index 4 days later.

RESULTS

The mean mucosal damage index and peritonitis score of group IV were significantly lower, and the mean tissue hydroxyproline level and anastomotic bursting pressure of group IV were significantly higher than those of group III.

CONCLUSION

The blockade of endothelin receptors by bosentan decreases the severity of iodoacetamide induced intestinal inflammation, increases the wound healing in the inflamed intestinal tissue, and decreases the severity of peritonitis.

A meta-analysis comparing conventional end-to-end anastomosis vs. other anastomotic configurations after resection in Crohn's disease

PURPOSE

This study compared outcomes between end-to-end anastomosis and other anastomotic configurations after intestinal resection for patients with Crohn's disease by using meta-analytical techniques.

METHODS

Comparative studies published between 1992 and 2005 of end-to-end anastomosis vs. other anastomotic configurations were included. Using a random effects model, end points evaluated were short-term complications and perianastomotic recurrence of Crohn's disease. Heterogeneity was assessed and sensitivity analysis was performed to account for bias in patient selection.

RESULTS

Eight studies (2 prospective, randomized, controlled trials; 1 nonrandomized, prospective; 5 nonrandomized, retrospective studies) reported on 661 patients who underwent 712 anastomoses, of which 383 (53.8 percent) were sutured end-to-end anastomosis and 329 (46.2 percent) were other anastomotic configurations (259 stapled side-to-side, 59 end-to-side or side-to-end, 11 stapled circular end-to-end). Anastomotic leak rate was significantly reduced in the other anastomotic configurations group (odds ratio (OR), 4.37; P = 0.02) and remained significantly lower in studies comparing only side-to-side anastomosis vs. end-to-end anastomosis (OR, 4.37; P = 0.02) and studies including only ileocolonic anastomosis (OR, 3.8; P = 0.05). Overall postoperative complications (OR, 2.64; P < 0.001), complications other than anastomotic leak (OR, 1.89; P = 0.04), and postoperative hospital stay (weighted mean difference, 2.81; P = 0.007) were significantly reduced in the side-to-side anastomosis group when considering studies comparing only side-to-side anastomosis vs. end-to-end anastomosis. There was no significant difference between the groups in perianastomotic recurrence and reoperation needed because of perianastomotic recurrence.

CONCLUSIONS

End-to-end anastomosis after resection for Crohn's disease may be associated with increased anastomotic leak rates. Side-to-side anastomosis may lead to fewer anastomotic leaks and overall postoperative complications, a shorter hospital stay, and a perianastomotic recurrence rate comparable to end-to-end anastomosis. Further randomized, controlled trials should be performed for confirmation.

A pilot study of intrastricture steroid versus placebo injection after balloon dilatation of Crohn's strictures

BACKGROUND & AIMS

Restricturing after ileocolonic resection for Crohn's disease is common. Colonoscopic balloon dilatation is effective but repeated dilatations often are required. Intrastricture steroid injection after balloon dilatation has been reported to reduce the need for repeat dilatation in retrospective series, but no randomized data are available.

METHODS

We performed a pilot study comparing local quadrantic injection of triamcinolone (40 mg total dose) after endoscopic balloon dilatation of Crohn's ileocolonic anastomotic strictures vs saline placebo. The primary end point was time to redilatation or surgery. Patients were followed up for 52 weeks.

RESULTS

Thirteen patients were randomized, 7 to steroid and 6 to placebo. Groups were well matched for baseline and dilatation characteristics. In the intention-to-treat analysis, 1 of 6 patients in the placebo group and 5 of 7 patients in the steroid group needed redilatation (log rank test P = .06; Cox regression P = .10; hazard ratio, 6.1; 95% confidence interval, 0.7-53.0). In the per-protocol analysis the differences were more significant (log rank test P = .03; Cox regression P = .07; hazard ratio, 7.7; 95% confidence interval, 0.9-67.9).

CONCLUSIONS

A single treatment of intrastricture triamcinolone injection did not reduce the time to redilatation after balloon dilatation of Crohn's ileocolonic anastomotic strictures and there was a trend toward a worse outcome. The use of this technique in clinical practice should be considered carefully until more data are available.

Regulation of intestinal epithelial gene expression in hypoxia

Mucosal hypoxia is intimately associated with chronic inflammation in the gastrointestinal tract in disease such as Crohn's disease. Under such conditions, intestinal epithelial cells may become a source of proinflammatory cytokines, including tumor necrosis factor alpha (TNFalpha), which actively contribute to ongoing inflammation through autocrine disruption of epithelial barrier function. These events are critically dependent upon alterations in the expression and function of the cAMF response element binding protein (CREB). Here we review our understanding of the molecular mechanisms underlying the regulation of CREB activity in intestinal epithelial cells in hypoxia.

Enteric-release glyceryl trinitrate in active Crohn's disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Mucosal ischaemia may contribute to the pathogenesis of Crohn's disease. Microvascular abnormalities have been found in colonic resection specimens, and mucosal levels of constitutive nitric oxide synthase are reduced.

AIM

To assess the efficacy of a novel, enteric-release formulation of the nitric oxide donor, glyceryl trinitrate, aimed at increasing the mucosal circulation and relaxing smooth muscle in the affected bowel.

METHODS

The trial was randomized, double-blind and placebo-controlled. Baseline disease activity was assessed by a structured symptom diary, with blood tests and a quality of life assessment. Patients with a Crohn's disease activity index of > or = 150 and < 450 were randomized to receive 12 weeks of either glyceryl trinitrate (initially 6 mg twice daily, increasing to 9 mg twice daily after 6 weeks) or an identical placebo. Assessments were repeated at 6 and 12 weeks.

RESULTS

Seventy patients (22 male) entered the study; 34 were given glyceryl trinitrate and 36 placebo. At 12 weeks, there were no differences between the treatment groups in terms of Crohn's disease activity index, pain, stool frequency, inflammatory markers or quality of life scores.

CONCLUSIONS

Enteric-release glyceryl trinitrate did not benefit patients with mild to moderately active Crohn's disease. Whilst ischaemia may contribute to the pathogenesis of Crohn's disease, our results fail to provide supportive evidence for this hypothesis.

Wide-lumen stapled anastomosis vs. conventional end-to-end anastomosis in the treatment of Crohn's disease

PURPOSE

Preanastomotic recurrence and stricturing after surgery for ileocolic Crohn's disease is a frequent, unexplained phenomena that may lead to prompt reoperation. The aim of this study was to determine whether a wide-lumen stapled anastomosis (side-to-side, functional end-to-end) provides better outcome than a conventional sutured end-to-end anastomosis

METHOD

A case-control comparative analysis of patients with Crohn's disease from two inflammatory bowel disease centers treated with wide-lumen stapled anastomosis and a matched (age and gender) group treated with conventional sutured end-to-end anastomosis was performed.

RESULTS

A total of 138 patients with Crohn's disease were treated, 69 with wide-lumen stapled anastomosis and 69 with conventional sutured end-to-end anastomosis. Preoperative therapy, number of previous resections, indication for operation, and length of bowel resected were similar in both groups. Fewer complications occurred after wide-lumen stapled anastomosis (P = 0.048). A total of 55 patients developed recurrent Crohn's disease symptoms, 39 (57 percent) in the conventional sutured end-to-end anastomosis and 16 (24 percent) in the wide-lumen stapled anastomosis group. Median follow-up was 70 and 46 months, respectively. After conventional sutured end-to-end anastomosis 18 reoperations were required, 15 for anastomotic stricture and 3 for fistulization. After wide-lumen stapled anastomosis three reoperations were necessary, two for stricture and one for fistulization. The cumulative reoperation rate for anastomotic recurrence was significantly lower (P = 0.017; log-rank test) for the wide-lumen stapled anastomosis group.

CONCLUSION

Wide-lumen stapled anastomosis is as safe as conventional sutured end-to-end anastomosis and results in a lower incidence of symptomatic recurrent Crohn's disease and need for reoperation. Further prospective study of the wide-lumen stapled anastomosis technique is necessary to define the precise role of this operation in patients with Crohn's disease.

Side-to-side stapled anastomosis may delay recurrence in Crohn's disease

PURPOSE

Perianastomotic recurrence after resection in Crohn's disease may be related to ischemia and subacute obstruction at the anastomosis. A technique designed to minimize these factors currently is being evaluated.

METHODS

From 1984 to 1997 69 patients underwent resection and primary anastomosis for symptomatic Crohn's disease (17 jejunal or ileal, 72 ileocolic, and 7 colocolic resections). Of these, 42 patients underwent functional end-to-end anastomoses with the use of linear cutting staplers (Proximate 75 mm or GIA 228 80 mm) and 27 patients underwent end-to-end sutured anastomoses.

RESULTS

In the stapled anastomosis group one (2 percent) patient required reoperation for recurrent symptoms at 46 months. Complications occurred in four (8 percent) patients (one enterocutaneous fistula, one wound infection, one abscess, and one ileus). There were no anastomotic leaks. The median postoperative stay was seven (range, 5-26) days. In the sutured anastomosis group 14 (43 percent) patients required 15 further resections for symptomatic recurrence at a median of 46 (range, 4-91) months. Complications occurred in six (17 percent) patients (two anastomotic leaks, two fistulas, one stricture, and one pulmonary embolus). The median postoperative stay was 10 (range, 6-28) days.

CONCLUSIONS

Functional end-to-end stapled anastomoses after resection for Crohn's disease may be associated with fewer complications than sutured anastomoses and may delay reoperation for symptomatic recurrence. Further evaluation of the technique is indicated.

Epithelial permeability induced by neutrophil transmigration is potentiated by hypoxia: role of intracellular cAMP

Mucosal tissues, such as the lung and intestine, are primary targets for ischemic damage. Under these conditions, neutrophil (polymorphonuclear leukocyte; PMN) infiltration into the protective epithelium has been implicated as a pathophysiologic mediator. Because PMN transepithelial migration results in increased paracellular permeability, and because our previous data revealed that epithelial hypoxia enhances PMN transmigration, we hypothesized that macromolecular permeability may be altered in epithelium exposed to hypoxia and reoxygenation (H/R) in the presence of PMNs. Human intestinal epithelia (T84) were grown on permeable supports, exposed to cellular hypoxia (pO2 20 torr) for 0-72 hr, and examined for increases in PMN-evoked permeability by using standard flux assays. Increasing epithelial hypoxia potentiated PMN-induced permeability of labeled paracellular tracers (size range 3-500 kD). Such increases were blocked by monoclonal antibody (mAb) to the PMN integrin CD11b (82 +/- 1% decreased compared with control mAb) and were partially blocked by anti-CD47 mAb (51 +/- 1%). Assessment of barrier recovery revealed that monolayers exposed to H/R were significantly diminished in their ability to reseal following PMN transmigration (recovery of 36 +/- 6% in H/R vs. 94 +/- 2% in normoxic controls). Because intracellular cyclic AMP (cAMP) has been demonstrated to regulate epithelial permeability, and because PMN-derived compound(s), (i.e., 5'-adenosine monophosphate; AMP) elevate epithelial cAMP, we examined the impact of hypoxia on epithelial cAMP responses. These experiments revealed that hypoxic epithelia were diminished in their ability to generate cAMP, and pharmacologic elevation (8-bromo-cAMP) of intracellular cAMP in hypoxic cells normalized both PMN-induced permeability changes and restoration of barrier function. These results support a role for PMN in increased intestinal permeability associated with reperfusion injury and imply a substantial role for cAMP signaling in maintenance of permeability during PMN transmigration.

Autocrine regulation of epithelial permeability by hypoxia: role for polarized release of tumor necrosis factor alpha

BACKGROUND & AIMS

The intestinal mucosa is lined by a monolayer of protective epithelial cells. This barrier is regulated by immune-derived factors such as interferon gamma (IFN-gamma). Because of the high volume of blood flow, the intestine is a primary target for hypoxic damage. We hypothesize that epithelial cytokine responses are regulated by hypoxia.

METHODS

T84 intestinal epithelial cells were used to assess alterations in permeability, major histocompatibility complex class II induction, cytokine receptor expression, and cytokine release in response to combinations of IFN-gamma and cellular hypoxia.

RESULTS

Hypoxia potentiated the influence of IFN-gamma on epithelial barrier function. Such responses were conferrable in a >/=10-kilodalton conditioned media fraction from hypoxic epithelia. Subsequent experiments identified this factor as epithelium-derived tumor necrosis factor alpha (TNF-alpha). Add-back of recombinant TNF-alpha in combination with IFN-gamma to normoxic epithelia recapitulated hypoxia and identified basolaterally polarized TNF-alpha receptor types I and II on intestinal epithelia. A similar pattern of TNF-alpha-receptor expression was observed on native intestinal epithelia. Specific inhibition of TNF-alpha using neutralizing antibody or alpha-N-phthalimidoglutarimide (thalidomide) resulted in reversal of the hypoxia-evoked responses.

CONCLUSIONS

These studies indicate that during hypoxia, epithelium-derived mediators such as TNF-alpha have the potential to regulate permeability through autocrine pathways.

Depressant effects of hypoxia and hypoglycaemia on neuro-effector transmission of guinea-pig intestine studied in vitro with a pharmacological model

1. Since intermittent ischaemia may play an important role in the aetiology of Inflammatory Bowel Disease, particularly Crohn's Disease, a pharmacological model of neuronal ischaemia was applied to guinea-pig isolated intestinal preparations to mimic the acute effects of reduced blood flow on intestinal motility. 2. Neuro-effector transmission and smooth muscle performance were examined in myenteric plexus-longitudinal muscle preparations of guinea-pig ileum exposed to sodium cyanide (NaCN), in order to inhibit oxidative phosphorylation, or to iodoacetic acid (IAA), to block glycolysis. Comparisons were made with the effects due to simple deprivation of oxygen or glucose. 3. Depression of cholinergic neuro-effector transmission induced by hypoxia or NaCN (effective concentration range 0.1-3 mM), given as separate treatments, singly or repetitively over 60-90 min, were apparent within 30 s and were reversible. The maximum inhibition was 90% and the IC50 for NaCN was 0.3 mM. A conspicuous component of these inhibitions was prejunctional. 4. Non-cholinergic neuro-effector contractions were inhibited by up to 90% by anoxia or NaCN but recovery was incomplete and slower than with cholinergic contractions. 5. Glucose-free solutions also caused a reversible failure of cholinergic neuro-effector transmission but of slower onset. In contrast, IAA (0.06-1 mM) abolished contractions irreversibly, apparently by a direct depressant effect on smooth muscle contraction. Unlike NaCN, IAA caused an initial potentiation of electrically-induced contractions, partly by a prejunctional potentiation of cholinergic neuro-effector transmission. 6. It is concluded that a disruption of intestinal activity in pathological conditions associated with intestinal ischaemia may result from disturbances in the function of enteric neurones.

Crohn's disease: pathogenesis and persistent measles virus infection

The Inflammatory Bowel Disease Study Group at the Royal Free Hospital School of Medicine has tested the hypothesis that the primary pathological abnormality in Crohn's disease is in the mesenteric blood supply. Early morphological studies involved arterial perfusion-fixation and either resin casting and scanning electron microscopy or vascular immunostaining of resected intestine affected by Crohn's disease. Granulomatous and lymphocytic damage to intramural blood vessels, even in macroscopically normal areas, was observed. We put forward possible mechanisms by which a chronic ischemic process might account for many of the idiosyncracies of Crohn's disease. It was proposed that persistent viral infection of the mesenteric microvascular endothelium might underly this vasculitic process; based on certain behavioral characteristics of measles virus, including its tropism for the submucosal endothelium of the intestine, this agent was investigated further. This report reviews the preliminary evidence from both epidemiological and basic scientific data for persistent measles virus in the intestine of patients with Crohn's disease. Possible mechanisms for virus persistence and subsequent reactivation are discussed. In conclusion, we believe that Crohn's disease may be a chronic granulomatous vasculitis in reaction to a persistent infection with measles virus within the vascular endothelium. This granulomatous inflammation, perhaps aggravated by either a hypercoagulable state or mechanical stress, results in the clinical features of Crohn's disease.

A vascular hypersensitivity model of acute multifocal gastrointestinal infarction

We have investigated the hypothesis that submucosal vasculitis may account for the patchy transmural inflammation observed in Crohn's disease. Test ferrets (N = 11) were sensitized to human albumin. Five days after the last sensitization injection, human albumin microspheres (15-150 microns diameter) were injected intraarterially into the mesenteric circulation of a defined loop of mid-gut. Six control ferrets showed no histological abnormality at either 48 hr or two weeks after intraarterial injection. At 48 hr, five of six presensitized ferrets demonstrated submucosal vasculitis with fibrinoid necrosis. In two cases there was transmural inflammation and mucosal ulceration. A further five presensitized ferrets received weekly subcutaneous human albumin injections following the mesenteric intraarterial injection of albumin microspheres: after two weeks one animal demonstrated mild perivascular inflammatory changes and another demonstrated vasculitis. One of the two animals with transmural inflammation and mucosal ulceration at 48 hr, and the animal with vasculitis at two weeks, had precipitating antibodies to human serum albumin. This model demonstrates that an immune-mediated submucosal vasculitis can sometimes result in discontinuous transmural inflammation of the intestinal wall.

Granulomatous vasculitis in Crohn's disease

This study investigated a possible vascular origin for granulomas in Crohn's disease. Twenty-four consecutive resected specimens of small and large intestinal Crohn's disease were preserved by arterial perfusion-fixation with 10% formol saline, at mean arterial pressure (100 mm Hg). Fifteen specimens contained granulomas on routine examination of H&E-stained sections. These 15 specimens were examined in detail using a range of immunohistochemical staining techniques to identify vascular structures and granulomas. A total of 485 granulomas were found, 85% of which were identified as being directly involved in vascular injury. The majority (77%) of granulomas were deep to the mucosa; they were found most frequently in the submucosa (42%). The techniques used in this study enhanced the recognition of granulomatous vasculitis. The results suggest that the majority of granulomas in Crohn's disease form within walls of blood vessels. Vascular localization of granulomatous inflammation suggests that the intestinal microvasculature contains an early element in the pathogenesis of Crohn's disease.