Inflammatory bowel disease

Apoptotic cells ameliorate chronic intestinal inflammation by enhancing regulatory B-cell function

Apoptosis is a programmed physiological death of unwanted cells, and handling of apoptotic cells (ACs) is thought to have profound effects on immune-mediated disorders. However, there is scant information regarding the role of ACs in intestinal inflammation, in which immune homeostasis is a major concern. To investigate this, we injected ACs into a severe combined immunodeficiency adoptive transfer model of chronic colitis in the presence and absence of cotransferred whole B or regulatory B cell (Breg)-depleted B cells. We also injected syngeneic ACs into AKR/N mice as a control and into milk fat globule-epidermal growth factor 8 knockout mice deficient of phagocytic function. Chronic colitis severity was significantly reduced in the AC as opposed to the phosphate-buffered saline group with cotransferred whole B cells. The AC-mediated effect was lost in the absence of B cells or presence of Breg-depleted B cells. In addition, ACs induced splenic B cells to secrete significantly increased levels of interleukin 10 in AKR/N mice but not milk fat globule-epidermal growth factor 8 knockout mice. Apoptotic leukocytes were induced by reactive oxygen species during granulocyte/monocyte apheresis therapy in rabbits and H2O2-induced apoptotic neutrophils ameliorated mice colitis. Our results indicate that ACs are protective only in the presence of B cells and phagocytosis of ACs induced interleukin 10 producing Bregs. Thus, the ameliorative effect seen in this study might have been exerted by AC-induced Bregs through increased production of the immunosuppressive cytokine interleukin 10, whereas an AC-mediated effect may contribute to the anti-inflammatory effect of granulocyte/monocyte apheresis as a novel therapeutic mechanism for inflammatory bowel disease.

Two-dimensional grayscale ultrasound and spectral Doppler waveform evaluation of dogs with chronic enteropathies

Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.

Utilidad pronóstica de la gammagrafía con leucocitos marcados 99mTc-HMPAO en la enfermedad inflamatoria intestinal

OBJECTIVE

The inflammatory bowel disease (EII) has a chronic evolution with a frequent relapses. There is no specific diagnosis method to detect the patients with a high risk to relapse. The aim of the work was to analyse the prognostic value of 99mTc-HMPAO leukocyte scintigraphy (LS) performed during an acute attack of EII.

MATERIAL AND METHODS

18 patients (mean age 32 +/- 10 years) admitted for an acute attack of EII has been prospectively studied (5 ulcerative colitis [UC] and 13 Cronh's disease [CD]), excluding patient with prior steroids or immunosuppressive therapy during the last year. LS were obtained in basal conditions and following 3 weeks of steroid treatment and the scintigraphic activity index (SAI) has been calculated. Colonoscopy has been done in all patients, and CDAI in CD and Truelove index in UC have been calculated. Patients were followed up for 1 year. In the evolution the therapy requirements as well as the good response to initial treatment have been evaluated.

RESULTS

All patients with UC and 4 patients with CD showed a SAI decrease > 50 % and all had a good clinical evolution. Only 2 out of the 9 patients with CD showing a IAG decrease < 50 % and had a good clinical evolution, the 7 remaining required additional medical treatment (immunosuppressors or surgery).

CONCLUSION

LS may be of prognostic value in the management of EII. A SAI decrease > 50 % at 3 weeks of steroid treatment indicates a good clinical evolution.

In vivo demonstration of T lymphocyte migration and amelioration of ileitis in intestinal mucosa of SAMP1/Yit mice by the inhibition of MAdCAM-1

The aetiology of Crohn's disease (CD) remains unknown. Since SAMP1/Yit mice have been reported to develop CD-like spontaneous enteric inflammation, such mice have been studied as an animal model of CD. In this study, using this model we examined T lymphocyte migration in microvessels of intestinal mucosa in vivo and the expression of adhesion molecules by immunohistochemistry. Fluorescence-labelled T lymphocytes isolated from AKR/J (control) mice were injected into the tail veins of recipient mice, and T lymphocyte migration in the postcapillary venules of Peyer's patches, submucosal microvessels, and villus capillaries of the terminal ileum was monitored using an intravital microscope. Adhesion of T lymphocytes was significantly increased in 35 week old SAMP1/Yit mice compared with that in AKR/J or 15 week old SAMP1/Yit mice. Immunohistochemical study showed increased infiltration of CD4, CD8 and beta7-integrin-positive cells and increased expression of MAdCAM-1 and VCAM-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against MAdCAM-1 and VCAM-1 significantly inhibited adhesion of T lymphocytes to microvessels of the terminal ileum, and anti-MAdCAM-1 antibody showed stronger suppressive effect than the anti-VCAM-1 antibody. Periodical administration of anti-MAdCAM-1 antibody twice a week for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice, but submucosal hypertrophy was not significantly suppressed. Anti-VCAM-1 antibody treatment failed to show significant resolution of ileitis. In addition, anti-MAdCAM-1 antibody treatment also attenuated established ileitis. The results demonstrate that, although MAdCAM-1 and VCAM-1 play an important role in T lymphocyte-endothelial cell interactions in SAMP1/Yit mice, MAdCAM-1 may be a more appropriate target for therapeutic modulation of chronic ileitis.

Pattern recognition and feature extraction of canine celiac and cranial mesenteric arterial waveforms: normal versus chronic enteropathy--a pilot study

In this pilot study, we hypothesize that waveform patterns of the celiac and cranial mesenteric arteries differ pre- and post-prandially in normal dogs compared to those with chronic enteropathy. We further suggest that it is possible to classify these findings according to the type of disease present. Eleven dogs with chronic enteropathy and eight normal dogs were examined. Doppler examinations were performed at times 0 (fasted), and at 20, 40, 60 and 90 min post-prandially. The waveform shapes were described and the following features were extracted: resistive and pulsatility index, mean maximum velocity, mean diastolic velocity, peak systolic velocity, early diastolic notch ratio and the deceleration time interval. Dogs with inflammatory bowel disease had either lower or absent flow at fasting in early diastole compared to the other groups. Resistive and pulsatility indices decreased during digestion in all groups except those with protein losing enteropathy. The increase in mean diastolic flow during digestion in affected dogs was either lacking (protein-losing enteropathy) or significantly lower (inflammatory bowel disease, P<0.05) compared to normal dogs. Dogs with chronic enteropathies had abnormal arterial waveform shapes and suboptimal increases in diastolic blood flow during digestion and these findings worsened with the severity of the histological lesions present. Doppler ultrasound of the celiac and mesenteric arteries has great potential to enhance our understanding of intestinal disease in conscious dogs.

In vivo colonoscopic optical coherence tomography for transmural inflammation in inflammatory bowel disease

BACKGROUND & AIMS

Transmural inflammation, a distinguishing feature of Crohn's disease (CD), cannot be assessed by conventional colonoscopy with mucosal biopsy. Our previous ex vivo study of histology-correlated optical coherence tomography (OCT) imaging on colectomy specimens of CD and ulcerative colitis (UC) showed that disruption of the layered structure of colon wall on OCT is an accurate marker for transmural inflammation of CD. We performed an in vivo colonoscopic OCT in patients with a clinical diagnosis of CD or UC using the previously established, histology-correlated OCT imaging criterion.

METHODS

OCT was performed in 40 patients with CD (309 images) and 30 patients with UC (292 images). Corresponding endoscopic features of mucosal inflammation were documented. Two gastroenterologists blinded to endoscopic and clinical data scored the OCT images independently to assess the feature of disrupted layered structure.

RESULTS

Thirty-six CD patients (90.0%) had disrupted layered structure, whereas 5 UC patients (16.7%) had disrupted layered structure (P < .001). Using the clinical diagnosis of CD or UC as the gold standard, the disrupted layered structure on OCT indicative of transmural inflammation had a diagnostic sensitivity and specificity of 90.0% (95% CI: 78.0%, 96.5%) and 83.3% (95% CI: 67.3%, 93.3%) for CD, respectively. The kappa coefficient in the interpretation of OCT images was 0.80 (95% CI: 0.75, 0.86, P < .001).

CONCLUSIONS

In vivo colonoscopic OCT is feasible and accurate to detect disrupted layered structure of the colon wall indicative of transmural inflammation, providing a valuable tool to distinguish CD from UC.

Blockade of PSGL-1 attenuates CD14+ monocytic cell recruitment in intestinal mucosa and ameliorates ileitis in SAMP1/Yit mice

The pathogenesis of Crohn's disease (CD) is not known. However, monocytes and macrophages are thought to play important roles in the development of mucosal inflammation. Therefore, in this study, we examined the role of monocyte-endothelial cell interactions in senescence-accelerated mouse P1 (SAMP1)/Yit mice, a murine model of spontaneous ileitis. Fluorescence-labeled CD14+ monocytic cells isolated from the spleen and mesenteric lymph nodes of AKR/J (control) mice were injected into the tail veins of recipient (AKR/J and SAMP1/Yit) mice, and migration in the postcapillary venules (PCV) of Peyer's patches, submucosal venules, and villus microvessels of the terminal ileum was monitored by using an intravital microscope. Rolling and adhesion of CD14+ monocytic cells in the PCV of Peyer's patches and microvessels of the terminal ileum were increased in SAMP1/Yit mice. An immunohistochemical study showed increased expression of P-selectin glycoprotein-1 (PSGL-1), P-selectin, and vascular cell adhesion molecule-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against these three adhesion molecules significantly inhibited adhesion of CD14+ monocytic cells to the PCV of Peyer's patches and microvessels of the terminal ileum, treatment with an anti-PSGL-1 monoclonal antibody (mAb) showing the strongest suppressive effect. Anti-PSGL-1 mAb also attenuated T cell adhesion in microvessels of intestinal mucosa. In addition, periodical administration of an anti-PSGL-1 mAb for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice. The results suggest that PSGL-1-P-selectin interaction plays an important role in monocyte-endothelial cell interactions and the development of ileitis in a murine model of CD and that the blockade of this adhesion molecule may be a novel strategy for treating CD.

Ex vivo histology-correlated optical coherence tomography in the detection of transmural inflammation in Crohn's disease

BACKGROUND AND AIMS

Distinguishing Crohn's disease (CD) from ulcerative colitis (UC) can be difficult. Transmural inflammation, a key feature of CD, cannot be assessed by conventional colonoscopy with biopsy. Optical coherence tomography (OCT) provides high-resolution, cross-sectional images of the gut wall and might become a new diagnostic tool. The aims of this study were to perform histology-correlated OCT on surgical specimens of CD and UC and to determine its diagnostic accuracy.

METHODS

Colectomy specimens from patients with a preoperative diagnosis of CD (N = 24) or UC (N = 24) were studied with OCT in the operating room. OCT and histopathology were assessed blindly, and diagnostic accuracy of OCT was assessed.

RESULTS

Eight preoperatively identified UC patients (33%) with transmural inflammation on postoperative histology were diagnosed with CD, and all 8 had a disrupted layered structure on OCT, a characteristic feature of transmural disease. Sixteen UC patients (67%) had superficial inflammation on histology; of them, 13 (81%) had an intact layered structure on OCT. All 24 preoperative CD patients had transmural inflammation on histology, and 23 (96%) had a disrupted layered structure on OCT. Of 585 histology-OCT image sets from the 48 patients, 152 sets (26%) had transmural inflammation on histology. The sensitivity and specificity for OCT to detect transmural disease were 86% and 91%, respectively.

CONCLUSIONS

Transmural inflammation, as characterized by disruption of the layered structure of colon wall on OCT, is an accurate marker for the diagnosis of CD. Ex vivo OCT predicted transmural inflammation on postoperative histopathology.

Antibody blockade of ICAM-1 and VCAM-1 ameliorates inflammation in the SAMP-1/Yit adoptive transfer model of Crohn's disease in mice

BACKGROUND & AIMS

Integrins (alpha(4) and beta(2)) and their endothelial ligands vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) play key roles in leukocyte recruitment to areas of inflammation. ICAM-1 and VCAM-1 are expressed in inflamed intestinal tissues. This study investigates a possible causative role of adhesion molecules ICAM-1, VCAM-1, and alpha(4) integrins in mediating the inflammatory response in a murine model of Crohn's disease (CD).

METHODS

CD4+ mesenteric lymph node cells from SAMP-1/Yit donor mice were adoptively transferred into major histocompatibility complex-matched severe combined immunodeficiency disease mice. Six weeks later, these mice were left untreated or treated for 3 days with monoclonal antibodies (mAbs) to ICAM-1, VCAM-1, or both, and alpha(4), or both ICAM-1 and alpha(4), dexamethasone, or nonblocking isotype control antibodies. On day 4 after treatment, tissues were investigated for expression of ICAM-1, VCAM-1, and for severity of inflammation using a semiquantitative inflammatory score. Dexamethasone treatment resolved all measures of intestinal inflammation.

RESULTS

Blocking either ICAM-1, VCAM-1, or alpha(4) integrins had no significant beneficial effect. However, blocking ICAM-1 and alpha(4), or blocking ICAM-1 and VCAM-1, showed a 70% resolution of the active inflammation, but not chronic inflammation.

CONCLUSIONS

These findings suggest that blocking ICAM-1 and VCAM-1 may have therapeutic benefit for the acute inflammatory component of Crohn's disease.