B2 adrenergic receptors and morphological changes of the enteric nervous system in colorectal adenocarcinoma

To study the morphology of the enteric nervous system and the expression of beta-2 adrenergic (B2A) receptors in primary colorectal cancer.METHODSIn this study, we included forty-eight patients with primary colorectal cancer and nine patients for control tissue from the excision of a colonic segment for benign conditions. We determined the clinicopathological features and evaluated the immunohistochemical expression pattern of B2A receptors as well as the morphological changes of the enteric nervous system (ENS). In order to assess statistical differences, we used the student t-test for comparing the means of two groups and one-way analysis of variance with Bonferroni’s post hoc analysis for comparing the means of more than two groups. Correlations were assessed using the Pearson’s correlation coefficient.RESULTSB2A receptors were significantly associated with tumor grading, tumor size, tumor invasion, lymph node metastasis (P < 0.05), while there were no statistically significant associations with gender, CRC location and gross appearance (P > 0.05). We observed, on one hand, a decrease of the relative area for both Auerbach and Meissner plexuses with the increase of the tumor grading, and on the other hand, an increase of the relative area of other nervous elements not in the Meissner plexus or in the Auerbach plexus with the tumor grading. For G1 tumors we found that epithelial B2A area showed an inverse correlation with the Auerbach plexus areas [r(14) = -0.531, P < 0.05], while for G2 tumors, epithelial B2A areas showed an indirect variation with both the Auerbach plexus areas [r(14) = -0.453, P < 0.05] and the Meissner areas [r(14) = -0.825, P < 0.01]. For G3 tumors, the inverse dependence increased for both Auerbach [r(14) = -0.587, P < 0.05] and Meissner [r(14) = -0.934, P < 0.05] plexuses.CONCLUSIONB2A receptors play an important role in colorectal carcinogenesis and can be utilized as prognostic factors. Furthermore, study of the ENS in colorectal cancer may lead to targeted molecular therapies.

Tumor neoangiogenesis detection by confocal laser endomicroscopy and anti-CD105 antibody:Pilot study

AIM: To evaluate neoangiogenesis in patients with colon cancer by two fluorescently labeled antibodies on fresh biopsy samples imaged with confocal laser endomicroscopy(CLE).METHODS: CLE is an imaging technique for gastrointestinal endoscopy providing in vivo microscopy at subcellular resolution.An important question in validating tumor angiogenesis is what proportion of the tumor vascular network is represented by preexisting parent tissue vessels and newly formed vessels.CD105(endoglin) represents a proliferation-associated endothelial cell adhesion molecule.In contrast to panendothelial markers,such as CD31,CD105 is preferentially expressed in activated endothelial cells that participate in neovascularization.Thus,we evaluated CD105 and CD31 expression from samples of ten patients with primary rectal adenocarcinoma,using a dedicated endomicroscopy system.A imaging software was used to obtain the Z projection of the confocal serial images from each biopsy sample previously combined into stacks.Vascular density and vessel diameters were measured within two 50 μm x 475 μm rectangular regions of interest centered in the middle of each image in the horizontal and vertical direction.The results were averaged over all the patients and were expressed as the mean ± SE.RESULTS: The use of an anti-CD105 antibody was found to be suitable for the detection of blood vessels in colon cancer.Whereas anti-CD31 antibodies stained blood vessels in both normal and pathologic colon equally,CD105 expression was observed primarily in malignant lesions,with little or no expression in the vessels of the normal mucosa(244.21 ± 130.7 vessels/mm3 in only four patients).The average diameter of antiCD105 stained vessels was 10.97 ± 0.6 μm in tumor tissue,and the vessel density was 2787.40 ± 134.8 vessels/mm3.When using the anti-CD31 antibody,the average diameter of vessels in the normal colon tissue was 7.67 ± 0.5 μm and the vessel density was 3191.60 ± 387.8 vessels/mm3,while in the tumors we obtained an average diameter of 10.88 ± 0.8 μm and a vessel density of 4707.30 ± 448.85 vessels/mm3.Thus,there were more vessels stained with CD31 than CD105(P < 0.05).The average vessel diameter was similar for both CD31 and CD105 staining.A qualitative comparison between CLE vs immunohistochemistry lead to similar results.CONCLUSION: Specific imaging and quantification of tumor microvessels are feasible in human rectal cancer using CLE examination and CD105 immunostaining of fresh tissue samples.