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Lynch syndrome is rarely associated with rectal cancer (RC) and thus, metachronous RC has been scarcely investigated. This study aimed to analyze the mucosal immune microenvironment in sporadic and metachronous RC. We analyzed the mucosal immune microenvironment in the 25 metachronous RCs present in the IMMUNOREACT 1 and 2 multicentre observational studies (624 patients). A panel of immune markers was retrospectively investigated at immunohistochemistry: CD3, CD4, CD8, CD8b, Tbet, FoxP3, PD-L1, MSH6, and PMS2 and CD80. Single-cell suspensions were subjected to flow-cytometry to determine the proportion of epithelial cells (pan-cytokeratin) acting as antigen-presenting cells (expressing CD80, CD86, HLA-ABC) and the proportion of activated CD8 + T cells (CD8 + positive for CD28, CD38), inhibitory T cells (CD3 + CTLA-4+) of activated CD4 + T helper cells (CD4 + CD25+) and activated T regulatory cells (CD4 + CD25 + FoxP3+). No mismatch repair gene deficiencies were observed in the patients. The previous history of colorectal adenoma was significantly more frequent in metachronous RC. In healthy epithelial cells, HLA-ABC expression was significantly higher in patients with metachronous RC. In therapy-naïve metachronous RC patients, a significantly lower level of circulating lymphocytes and CD3 + T-cell infiltration in the healthy mucosa surrounding the RC was observed compared to patients with non-metachronous cancer. Our study supports the hypothesis that metachronous RC can occur in a cancerization field in patients with weak systemic and local immune systems. The peculiar site of RC makes the mismatch-repair genes deficiency in metachronous cancer onset less relevant., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Transanal excision of rectal cancer can be considered the definitive surgical treatment if the depth spread is T1 or lower, and the lesion is completely included within the resection margin. This study aims to analyze the immune microenvironment in healthy rectal mucosa as a possible predictor of tumor infiltration depth, lateral tumor spread, and recurrence of rectal cancer after transanal local excision., Methods: This study is a subanalysis of data from the IMMUNOREACT 1 and 2 trials (NCT04915326 and NCT04917263, respectively) including all the patients who underwent transanal excision of rectal cancer. This multicentric study collected healthy mucosa surrounding the neoplasms of patients with rectal cancer. A panel of immune markers was investigated at immunohistochemistry: CD3, CD4, CD8, CD8β, Tbet, FoxP3, PD-L1, MSH6, and PMS2 and CD80. Flow cytometry determined the proportion of epithelial cells expressing CD80, CD86, CD40, HLA ABC or HLA DR and the proportion of activated CD8+ T cells, CD4+ Th1 cells, and Treg., Results: Receiver operating characteristic curve analysis for predicting deep tumor spread showed an area under the curve of 0.70 (95% confidence interval: 0.60-0.80) for CD25+FoxP3+ cell rate and 0.74 (95% confidence interval: 0.53-0.92) for CK+CD86+ cell rate. Receiver operating characteristic curve analysis for predicting lateral tumor spread showed an area under the curve of 0.82 (95% confidence interval: 0.61-0.99) for CD8+CD38+ MFI, 0.96 (95% confidence interval: 0.85-0.99) for CD8β infiltration, and 0.97 (95% confidence interval: 0.87-0.99) for CK+HLAabc+ cell rate. Receiver operating characteristic curve analysis for predicting recurrence showed an area under the curve of 0.93 (95% confidence interval: 0.76-0.99) for CD8+CD38+ MFI and 0.94 (95% confidence interval: 0.78-0.99) for CD8+CD28+ MFI. Low CD8+CD38+ MFI and low CD8+CD28+ MFI were associated with shorter disease-free survival (P = .025 and P = .021, respectively)., Conclusion: Our study showed that the association between the high proportion of epithelial cells acting as presenting cells and deep or lateral tumor spread may be explained by the presence of a greater tumor load at the site. Moreover, it showed that weak activation of CD8+ T cells within the rectal mucosa is associated with lateral tumor spread and eventually a higher recurrence rate. The mucosal level of CD8β infiltration detected at immunohistochemistry might be tested as a marker of lateral tumor spread and potentially translated into clinical practice., Competing Interests: Conflict of Interest/Disclosure The authors have no relevant financial disclosures., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Long-term daily use of aspirin reduces incidence and mortality due to colorectal cancer (CRC). This study aimed to analyze the effect of aspirin on the tumor microenvironment, systemic immunity, and on the healthy mucosa surrounding cancer., Methods: Patients with a diagnosis of CRC operated on from 2015 to 2019 were retrospectively analyzed (METACCRE cohort). Expression of mRNA of immune surveillance-related genes (PD-L1, CD80, CD86, HLA I, and HLA II) in CRC primary cells treated with aspirin were extracted from Gene Expression Omnibus-deposited public database (GSE76583). The experiment was replicated in cell lines. The mucosal immune microenvironment of a subgroup of patients participating in the IMMUNOREACT1 (ClinicalTrials.gov NCT04915326) project was analyzed with immunohistochemistry and flow cytometry., Results: In the METACCRE Cohort, 12% of 238 patients analyzed were aspirin users. Nodal metastasis was significantly less frequent (p = .008) and tumor-infiltrating lymphocyte infiltration was higher (p = .02) among aspirin users. In the CRC primary cells and selected cell lines, CD80 mRNA expression was increased following aspirin treatment (p = .001). In the healthy mucosa surrounding rectal cancer, the ratio of CD8/CD3 and epithelial cells expressing CD80 was higher in aspirin users (p = .027 and p = .034, respectively)., Conclusions: These data suggested that regular aspirin use may have an active role in enhancing immunosurveillance against CRC., (© 2024 American Cancer Society.)

Anesthesia for patients with Steinert's syndrome (myotonic dystrophy, MD) is a challenge for the anaesthetist. MD is a multisystemic disease and the neuromuscular symptoms can be associated with sleep apnea, endocrine disorders (diabetes, hypogonadism, hypothyroidism), cardiac, gastroenteric or cognitive disorders (mental deficiency, attention disorders). The diagnosis is facilitated when one or more of these symptoms are associated with the neuromuscular symptoms; however, the latter are not always present at the onset, which makes the diagnosis of MD a difficult and often late one. The choice of drugs and the choice of anesthesia in these patients can be very challenging for many reasons. A myotonic crisis can be triggered by several factors including hypothermia, shivering and mechanical or electrical stimulation. These patients are very sensitive to the usual anesthetics such as hypnotics and paralyzing agents (both depolarizing and nondepolarizing). The following case report describes pathophysiological considerations and a technique for anaesthesia during thoracic surgery that has been able to assure hemodynamic peroperative stability, early extubation and prolonged respiratory autonomy in a patient affected by this genetic disorder.

Experiments were designed to characterize endothelin receptors in bronchi and parenchyma of transplanted lungs during acute rejection. Third-order bronchi from autografted or allografted lungs were either cut into rings and suspended in organ chambers for the measurement of isometric force or frozen for isolation of membrane proteins. Lung parenchyma was prepared for histology or isolation of membrane protein. The grade of rejection was 2.74+/-0.17 (n= 19) in allotransplanted lungs; evidence of infection was present in 58% of the transplanted lungs. In organ chamber experiments, endothelin 1 (which stimulates endothelin A receptors) caused comparable contraction of bronchi from autotransplanted and allotransplanted rejecting lungs. Endothelin 3 (which stimulates endothelin A and B receptors) caused contractions of bronchi from autotransplanted lungs which were not different from those caused by endothelin 1. In contrast, contractions caused by endothelin 3 were reduced in bronchi from rejecting allotransplanted lungs. The magnitude of contractions caused by endothelin 3 was reduced further when infection was present with rejection. Competitive inhibition of 125I-endothelin 1 by endothelin 3 was significant for a two-site binding model in membranes prepared from all bronchi and lung parenchyma. The total number of binding sites (Bmax) was reduced significantly in bronchi and parenchyma from rejecting lungs with or without infection. The relative proportions of high-affinity and low-affinity binding sites did not change. Affinities of both high- and low-affinity receptors were not altered with rejection. These results indicate that at least two subtypes of endothelin receptors are present on canine bronchial smooth muscle and parenchyma. The number of endothelin receptors associated with bronchial contractions is reduced with rejection of lung allografts.

Endothelin-1 (ET-1) is found in bronchoalveolar lavage fluid in patients following lung transplantation. ET-1 causes contraction of isolated pulmonary vessels and bronchi and stimulates proliferation of smooth muscle cells in culture. Therefore, ET-1 could contribute to the smooth muscle hyperplasia and stromal proliferation seen in chronic rejection of lung allografts. Experiments were designed to determine whether (1) ET-1 stimulates proliferation of pulmonary tissue, (2) proliferation is increased in rejecting allotransplanted lungs, (3) endothelin-A receptors mediate the proliferative response, and (4) ET-1 is produced by activated infiltrating immunocompetent cells. Lung organ cultures were prepared from unoperated dogs and dogs with rejecting single lung allografts. Incubation of organ cultures from unoperated dogs with ET-1 (10(-9) to 10(-7) M)) increased positive staining for proliferation cell nuclear antigen (PCNA) in lung parenchyma. PCNA staining was not decreased by the endothelin-A antagonist BQ123 (10(-6) M). In addition, immunostaining for endothelin-B receptors was present in sections of unoperated but not rejecting lungs. PCNA staining in lung cultures from rejecting allotransplanted dogs was significantly greater than that from unoperated dogs. Positive immunohistochemical staining for ET-1 was found in mononuclear cells infiltrating rejecting transplanted lungs. In conclusion, exogenous ET-1 is mitogenic in lung organ cultures through receptors other than endothelin-A. Proliferation in rejecting transplanted lungs is increased compared with unoperated lungs. Mononuclear cells may be a source of endothelin-1 in the rejecting lung. ET-1, therefore could, in synergism with other cytokines, contribute to acute and chronic pathological changes seen in pulmonary rejection.

Purpose: Experiments were designed to determine whether or not leukocytes activated by acute pulmonary rejection cause contractions of isolated pulmonary arteries., Methods and Results: Separate suspensions of (a) polymorphonuclear cells (> 95%) and (b) mononuclear cells (85% lymphocytes/10% monocytes/5% polymorphonuclear cells), respectively, were obtained from the arterial blood of four groups of adult male mongrel dogs: unoperated dogs (controls), dogs with single-lung autotransplants, dogs with rejecting single-lung allotransplants, and unoperated dogs treated with the same immunosuppressants as allotransplanted dogs. These suspensions were added to rings of control intralobar pulmonary arteries suspended in organ chambers for measurement of isometric force. The endothelium was removed mechanically from selected rings. No significant change in basal tension of pulmonary arterial rings occurred by adding suspensions of polymorphonuclear cells from any of the four groups of dogs. Significant cell-number-dependent increases in tension occurred with suspensions of mononuclear cells from unoperated dogs, autotransplanted dogs, and unoperated, medicated dogs. These increases in tension were less in rings with compared to those without endothelium. Addition of a synthetic analogue of L-arginine abolished this difference. Suspensions of mononuclear cells from rejecting allotransplanted dogs caused significantly greater contractions in rings with endothelium than those observed with suspended cells from either unoperated, autotransplanted dogs or unoperated, medicated dogs. Addition of superoxide dismutase plus catalase or an antagonist of endothelin-A receptors (BQ-123) reduced contractions in rings with endothelium but not in those without endothelium to suspensions of mononuclear cells from rejecting allotransplanted dogs., Conclusions: The results of this study suggest that mononuclear cells cause contraction of pulmonary arteries, which can be partially inhibited by endothelium-derived nitric oxide. However, if the mononuclear cells are activated by acute pulmonary rejection, contractions are no longer inhibited by the endothelium. Under conditions of rejection, contractions are mediated in part by oxygen radicals and endothelin(s).