The UDP-glucose/P2Y14 receptor axis promotes eosinophil-dependent large intestinal inflammation.

Ulcerative colitis (UC) is a chronic disorder of the large intestine with inflammation and ulceration. The incidence and prevalence of UC have been rapidly increasing worldwide, but its etiology remains unknown. In patients with UC, the accumulation of eosinophils in the large intestinal mucosa is associated with increased disease activity. However, the molecular mechanism underlying the promotion of intestinal eosinophilia in patients with UC remains poorly understood. Here, we show that uridine diphosphate (UDP)-glucose mediates the eosinophil-dependent promotion of colonic inflammation via the purinergic receptor P2Y14. The expression of P2RY14 mRNA was upregulated in the large intestinal mucosa of patients with UC. The P2Y14 receptor ligand UDP-glucose was increased in the large intestinal tissue of mice administered dextran sodium sulfate (DSS). In addition, P2ry14 deficiency and P2Y14 receptor blockade mitigated DSS-induced colitis. Among the large intestinal immune cells and epithelial cells, eosinophils highly expressed P2ry14 mRNA. P2ry14-/- mice transplanted with wild-type bone marrow eosinophils developed more severe DSS-induced colitis compared with P2ry14-/- mice that received P2ry14-deficient eosinophils. UDP-glucose prolonged the lifespan of eosinophils and promoted gene transcription in the cells through P2Y14 receptor-mediated activation of ERK1/2 signaling. Thus, the UDP-glucose/P2Y14 receptor axis aggravates large intestinal inflammation by accelerating the accumulation and activation of eosinophils.

BRAF V600E-induced distinct DNA damage response defines the therapeutic potential of p53 activation for TP53 wild-type colorectal cancer.

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

Postoperative venous thromboembolism after surgery for locally recurrent rectal cancer.

BACKGROUND: Local recurrence is common after curative resections of rectal cancer. Surgical resection is considered a primary curative treatment option for patients with locally recurrent rectal cancer (LRRC). LRRC often requires a combined resection of other organs, especially in the case of posterior recurrence, which requires a combined resection of the sacrum, making the surgery highly invasive. Venous thromboembolism (VTE) is one of the lethal complications in the postoperative period, particularly in the field of pelvic surgery. We found no reports regarding the risks of postoperative VTE in surgery for LRRC, a typical highly invasive procedure in the field of colorectal surgery. This study aims to evaluate the risk of postoperative VTE in surgery for LRRC patients. METHODS: From April 2010 to March 2022, a total of 166 patients underwent surgery for LRRC in the pelvic region at our institutions. Clinicopathological background and VTE incidence were compared retrospectively. RESULTS: Among the 166 patients included in the study, 55 patients (33.1%) needed sacral resection. Pharmacological prophylaxis for prevention of VTE was performed in 121 patients (73.3%), and the incidence of VTE was 9.09% (5/55 patients) among those who underwent surgery for LRRC with sacral resection, while it was 1.8% (2/111 patients) in those without sacral resection. In univariate analysis, the combination with sacral resection was identified as a risk factor for VTE in surgery for LRRC (p = 0.047). CONCLUSIONS: This study demonstrates that surgery for LRRC combined with sacral resection could be a significant risk factor for VTE.

Association between Sense of Coherence, Disease-Specific Symptoms, and Health-Related Quality of Life among Japanese Patients with Ulcerative Colitis: A Cross-Sectional Study.

INTRODUCTION: We examined the associations among disease-related symptoms, health-related quality of life (HRQOL), and sense of coherence (SOC) in Japanese patients with ulcerative colitis (UC). METHODS: This cross-sectional survey involved patients and physicians at 23 hospitals specializing in UC treatment in Japan (December 2019-December 2020). Multiple linear regression analysis was performed using scores on the Mental Health and General Health subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey as outcomes and SOC as the main independent variable. Scores on the Inflammatory Bowel Disease Questionnaire (IBDQ) and Fecal Incontinence Quality of Life Scale (FIQL) were used to measure the effect of disease-related symptoms. The moderating effect of symptoms on the association between HRQOL and SOC was also tested. RESULTS: SOC was positively and independently associated with HRQOL (Mental Health: ß = 0.43, 95% confidence interval [CI] = 0.24-0.61, p < 0.001; General Health: ß = 0.41, 95% CI = 0.23-0.59, p < 0.001). The association of SOC with Mental Health scores did not differ by symptoms, whereas its association with General Health was attenuated by symptoms (interaction term of IBDQ by SOC: ß = -0.0082, 95% CI = -0.017 to 0.00064, p = 0.07; that of FIQL by SOC: ß = -0.0052, 95% CI = -0.011 to 0.0010, p = 0.10). CONCLUSIONS: SOC affected mental health independently, and its protective association with general health perception was affected by symptoms. Further research is required to determine the most effective use of SOC in interventions to improve HRQOL in patients with UC.

The ATP-hydrolyzing ectoenzyme E-NTPD8 attenuates colitis through modulation of P2X4 receptor-dependent metabolism in myeloid cells.

Extracellular adenosine triphosphate (ATP) released by mucosal immune cells and by microbiota in the intestinal lumen elicits diverse immune responses that mediate the intestinal homeostasis via P2 purinergic receptors, while overactivation of ATP signaling leads to mucosal immune system disruption, which leads to pathogenesis of intestinal inflammation. In the small intestine, hydrolysis of luminal ATP by ectonucleoside triphosphate diphosphohydrolase (E-NTPD)7 in epithelial cells is essential for control of the number of T helper 17 (Th17) cells. However, the molecular mechanism by which microbiota-derived ATP in the colon is regulated remains poorly understood. Here, we show that E-NTPD8 is highly expressed in large-intestinal epithelial cells and hydrolyzes microbiota-derived luminal ATP. Compared with wild-type mice, Entpd8-/- mice develop more severe dextran sodium sulfate-induced colitis, which can be ameliorated by either the depletion of neutrophils and monocytes by injecting with anti-Gr-1 antibody or the introduction of P2rx4 deficiency into hematopoietic cells. An increased level of luminal ATP in the colon of Entpd8-/- mice promotes glycolysis in neutrophils through P2x4 receptor-dependent Ca2+ influx, which is linked to prolonged survival and elevated reactive oxygen species production in these cells. Thus, E-NTPD8 limits intestinal inflammation by controlling metabolic alteration toward glycolysis via the P2X4 receptor in myeloid cells.

Cancer-specific tissue-resident memory T-cells express ZNF683 in colorectal cancer.

BACKGROUND: Tissue-resident memory T (Trm) cells are associated with cytotoxicity not only in viral infection and autoimmune disease pathologies but also in many cancers. Tumour-infiltrating CD103+ Trm cells predominantly comprise CD8 T cells that express cytotoxic activation and immune checkpoint molecules called exhausted markers. This study aimed to investigate the role of Trm in colorectal cancer (CRC) and characterise the cancer-specific Trm. METHODS: Immunochemical staining with anti-CD8 and anti-CD103 antibodies for resected CRC tissues was used to identify the tumour-infiltrating Trm cells. The Kaplan-Meier estimator was used to evaluate the prognostic significance. Cells immune to CRC were targeted for single-cell RNA-seq analysis to characterise cancer-specific Trm cells in CRC. RESULTS: The number of CD103+/CD8+ tumour-infiltrating lymphocytes (TILs) was a favourable prognostic and predictive factor of the overall survival and recurrence-free survival in patients with CRC. Single-cell RNA-seq analysis of 17,257 CRC-infiltrating immune cells revealed a more increased zinc finger protein 683 (ZNF683) expression in cancer Trm cells than in noncancer Trm cells and in high-infiltrating Trm cells than low-infiltrating Trm in cancer, with an upregulated T-cell receptor (TCR)- and interferon-γ (IFN-γ) signalling-related gene expression in ZNF683+ Trm cells. CONCLUSIONS: The number of CD103+/CD8+ TILs is a prognostic predictive factor in CRC. In addition, we identified the ZNF683 expression as one of the candidate markers of cancer-specific Trm cells. IFN-γ and TCR signalling and ZNF683 expression are involved in Trm cell activation in tumours and are promising targets for cancer immunity regulation.

Crohn's Disease-Associated Anorectal Cancer Has a Poor Prognosis With High Local Recurrence: A Subanalysis of the Nationwide Japanese Study.

INTRODUCTION: Colorectal cancer (CRC) is one of the major life-threatening complications in patients with Crohn's disease (CD). Previous studies of CD-associated CRC (CD-CRC) have involved only small numbers of patients, and no large series have been reported from Asia. The aim of this study was to clarify the prognosis and clinicopathological features of CD-CRC compared with sporadic CRC. METHODS: A large nationwide database was used to identify patients with CD-CRC (n = 233) and sporadic CRC (n = 129,783) over a 40-year period, from 1980 to 2020. Five-year overall survival (OS), recurrence-free survival (RFS), and clinicopathological characteristics were investigated. The prognosis of CD-CRC was further evaluated in groups divided by colon cancer and anorectal cancer (RC). Multivariable Cox regression analysis was used to adjust for confounding by unbalanced covariables. RESULTS: Compared with sporadic cases, patients with CD-CRC were younger; more often had RC, multiple lesions, and mucinous adenocarcinoma; and had lower R0 resection rates. Five-year OS was worse for CD-CRC than for sporadic CRC (53.99% vs 71.17%, P < 0.001). Multivariable Cox regression analysis revealed that CD was associated with significantly poorer survival (hazard ratio 2.36, 95% confidence interval: 1.54-3.62, P < 0.0001). Evaluation by tumor location showed significantly worse 5-year OS and RFS of CD-RC compared with sporadic RC. Recurrence was identified in 39.57% of CD-RC cases and was mostly local. DISCUSSION: Poor prognosis of CD-CRC is attributable primarily to RC and high local recurrence. Local control is indispensable to improving prognosis.

Effect of Biologics on the Risk of Advanced-Stage Inflammatory Bowel Disease-Associated Intestinal Cancer: A Nationwide Study.

INTRODUCTION: The aim of this study was to evaluate the effect of biologics on the risk of advanced-stage inflammatory bowel disease (IBD)-associated intestinal cancer from a nationwide multicenter data set. METHODS: The medical records of patients with Crohn's disease (CD) and ulcerative colitis (UC) diagnosed with IBD-associated intestinal neoplasia (dysplasia or cancer) from 1983 to 2020 were included in this study. Therapeutic agents were classified into 3 types: biologics, 5-aminosalicylic acid, and immunomodulators. The pathological cancer stage was compared based on the drug used in both patients with CD and UC. RESULTS: In total, 1,042 patients (214 CD and 828 UC patients) were included. None of the drugs were significantly associated with cancer stage in the patients with CD. In the patients with UC, an advanced cancer stage was significantly associated with less use of biologics (early stage: 7.7% vs advanced stage: 2.0%, P < 0.001), 5-aminosalicylic acid, and immunomodulators. Biologic use was associated with a lower incidence of advanced-stage cancer in patients diagnosed by regular surveillance (biologics [-] 24.5% vs [+] 9.1%, P = 0.043), but this was not the case for the other drugs. Multivariate analysis showed that biologic use was significantly associated with a lower risk of advanced-stage disease (odds ratio = 0.111 [95% confidence interval, 0.034-0.356], P < 0.001). DISCUSSION: Biologic use was associated with a lower risk of advanced IBD-associated cancer in patients with UC but not with CD. The mechanism of cancer progression between UC and CD may be different and needs to be further investigated.

Deep Learning Analysis of Histologic Images from Intestinal Specimen Reveals Adipocyte Shrinkage and Mast Cell Infiltration to Predict Postoperative Crohn Disease.

Most patients with Crohn disease (CD), a chronic inflammatory gastrointestinal disease, experience recurrence despite treatment, including surgical resection. However, methods for predicting recurrence remain unclear. This study aimed to predict postoperative recurrence of CD by computational analysis of histopathologic images and to extract histologic characteristics associated with recurrence. A total of 68 patients who underwent surgical resection of the intestine were included in this study and were categorized into two groups according to the presence or absence of postoperative disease recurrence within 2 years after surgery. Recurrence was defined using the CD Activity Index and the Rutgeerts score. Whole-slide images of surgical specimens were analyzed using deep learning model EfficientNet-b5, which achieved a highly accurate prediction of recurrence (area under the curve, 0.995). Moreover, subserosal tissue images with adipose cells enabled highly accurate prediction. Adipose cell morphology showed significant between-group differences in adipose cell size, cell-to-cell distance, and cell flattening values. These findings suggest that adipocyte shrinkage is an important histologic characteristic associated with recurrence. Moreover, there was a significant between-group difference in the degree of mast cell infiltration in the subserosa. These findings show the importance of mesenteric adipose tissue in patient prognosis and CD pathophysiology. These findings also suggest that deep learning-based artificial intelligence enables the extraction of meaningful histologic features.

Cancer Stem Cells Persist Despite Cellular Damage, Emergence of the Refractory Cell Population.

PURPOSE: Cancer stem cells (CSCs) are responsible for chemotherapy resistance and have unique properties that protect them from chemotherapy. Investigating CSCs may help to identify the population that is more resistant to treatments, leading to recurrence. We evaluated persisting CSCs, emerging after chemotherapy that cause tumor recurrence. METHODS: Using human colorectal cancer organoids prepared from surgical specimens, we looked at changes in CSCs, the emergence and changes in the original population, which single-cell analysis identified. RESULTS: With regards to changes in cancer stem cell markers, CD44 showed low levels after 5-fluorouracil administration. Once the CD44-ve population was sorted and cultured, the CD44+ve population gradually emerged, and the CD44-ve population decreased. Compared with the CD44-ve population of an organoid parent, the CD44-ve population proliferated after chemotherapeutic agent stimulation. The CD44-ve population was derived from the CD44+ve population before chemotherapeutic agents. In addition, when the CD44 variants were evaluated, the CD44v9 population remained. In single-cell analysis, we found that POU5F1 was highly expressed in the CD44low population. Velocity analysis showed that the CD44-ve population was induced after chemotherapy and expressed POU5F1. POU5F1-EGFP-Casp9 transfected organoids resulted in the appearance of a CD44-ve population after administration of a chemotherapeutic reagent. Both in vivo and in vitro, the dimerizer administration inhibited tumor growth significantly. CONCLUSIONS: POU5F1 is involved in chemotherapy resistance in relation to stemness. For the treatment against refractory tumors, such as the recurrence after chemotherapy, the treatment should target the emerging specific population such as CD44 (or CD44v9) and proliferative cancer cells.

Simple Detection and Culture of Circulating Tumor Cells from Colorectal Cancer Patients Using Poly(2-Methoxyethyl Acrylate)-Coated Plates.

Here we aimed to establish a simple detection method for detecting circulating tumor cells (CTCs) in the blood sample of colorectal cancer (CRC) patients using poly(2-methoxyethyl acrylate) (PMEA)-coated plates. Adhesion test and spike test using CRC cell lines assured efficacy of PMEA coating. A total of 41 patients with pathological stage II-IV CRC were enrolled between January 2018 and September 2022. Blood samples were concentrated by centrifugation by the OncoQuick tube, and then incubated overnight on PMEA-coated chamber slides. The next day, cell culture and immunocytochemistry with anti-EpCAM antibody were performed. Adhesion tests revealed good attachment of CRCs to PMEA-coated plates. Spike tests indicated that ~75% of CRCs from a 10-mL blood sample were recovered on the slides. By cytological examination, CTCs were identified in 18/41 CRC cases (43.9%). In cell cultures, spheroid-like structures or tumor-cell clusters were found in 18/33 tested cases (54.5%). Overall, CTCs and/or growing circulating tumor cells were found in 23/41 CRC cases (56.0%). History of chemotherapy or radiation was significantly negatively correlated with CTC detection (p = 0.02). In summary, we successfully captured CTCs from CRC patients using the unique biomaterial PMEA. Cultured tumor cells will provide important and timely information regarding the molecular basis of CTCs.

[A Case of Squamous Cell Carcinoma of the Lower Rectum].

A 61-year-old man presented with dyschezia, and further examination revealed squamous cell carcinoma of the lower rectum invading the bladder and seminal vesicles. The clinical diagnosis was squamous cell carcinoma of the lower rectum, cT4b(bladder and seminal vesicle)N0M0, cStage Ⅱc. Neoadjuvant chemoradiotherapy was administered with external irradiation of the entire pelvis(50.4 Gy/28 Fr)and chemotherapy with 5-fluorouracil, Leucovorin, and oxaliplatin(FOLFOX). Once tumor shrinkage was observed 3 months after chemoradiotherapy, laparoscopic total pelvic exenteration with TaTME approach was performed. The patient was discharged on the 26th postoperative day without any postoperative complications. Histopathological examination showed only squamous cell carcinoma component with Grade 1a histological treatment effect. The pathological diagnosis was ypT4b(bladder, seminal vesicle)ypN0cM0, ypStage Ⅱc. The patient was alive without any recurrence 6 months after surgery.

Low G9a expression is a tumor progression factor of colorectal cancer via IL-8 promotion.

The histone methyltransferase G9a is expressed in various types of cancer cells, including colorectal cancer (CRC) cells. Interleukin 8 (IL)-8, also known as C-X-C motif chemokine ligand 8 (CXCL8), is a chemokine that plays a pleiotropic function in the regulation of inflammatory responses and cancer development. Here, we examined the relationship between G9a and IL-8 and the clinical relevance of this association. We immunohistochemically analyzed 235 resected CRC samples to correlate clinical features. Samples with high G9a expression had better overall survival and relapse-free survival than those with low G9a expression. Univariate and multivariate analyses demonstrated that low G9a expression remained a significant independent prognostic factor for increased disease recurrence and decreased survival (P < 0.05). G9a was expressed at high levels in commercially available CRC cell lines HCT116 and HT29. Knockdown of G9a by siRNA, shRNA or the G9a-specific inhibitor BIX01294 upregulated IL-8 expression. The number of spheroids was significantly increased in HCT116 cells with stably suppressed G9a expression, and the number of spheroids was significantly decreased in HCT116 cells with stably suppressed IL-8 expression. Thus, the suppression of IL-8 by G9a may result in a better prognosis in CRC cases with high G9a expression. Furthermore, G9a may suppress cancer stemness and increase chemosensitivity by controlling IL-8. Therefore, G9a is a potential novel marker for predicting CRC prognosis, and therapeutic targeting of G9a in CRC should be controversial.

PLXND1/SEMA3E Promotes Epithelial-Mesenchymal Transition Partly via the PI3K/AKT-Signaling Pathway and Induces Heterogenity in Colorectal Cancer.

Colorectal cancer (CRC) is a major cause of cancer-related deaths. Metastasis is enhanced through epithelial-mesenchymal transition (EMT), a process primarily induced by the transforming growth factor beta (TGF-ß)-mediated canonical Smad pathway. This study focused on plexin D1 (PLXND1), a chemoreceptor for the ligand SEMA3E to mechanosensory, showing that PLXND1 induces EMT via activation of the PI3K/AKT pathway in CRC cells. The findings showed that PLXND1-knockdown decreases cell migration and invasion significantly, and that the binding of p61-SEMA3E to the PLXND1 enhances the invasiveness and migration through EMT. Furin inhibitor suppresses EMT, decreasing cell migration and invasion. Furin cleaves full-length SEMA3E and converts it to p61-SEMA3E, suggesting that furin inhibitors block PLXND1 and p61-SEMA3E binding. Furin is a potential therapeutic target for the purpose of suppressing EMT by inhibiting the binding of p61-SEMA3E to PLXND1. In vivo experiments have shown that PLXND1-knockdown suppresses EMT. Mesenchymal cells labeled with ZEB1 showed heterogeneity depending on PLXND1 expression status. The high-expression group of PLXND1 in 182 CRC samples was significantly associated with poor overall survival compared with the low-expression group (P = 0.0352, median follow-up period of 60.7 months) using quantitative real-time polymerase chain reaction analysis. Further research is needed to determine whether cell fractions with a different expression of PLXND1 have different functions.

Development and evaluation of a Japanese prediction model for low anterior resection syndrome after rectal cancer surgery.

BACKGROUND: Low anterior resection syndrome (LARS) is the most common complication after rectal cancer resection. We aimed to identify LARS' predictive factors and construct and evaluate a predictive model for LARS. METHODS: This retrospective study included patients with rectal cancer more than 1 year after laparoscopic or robotic-assisted surgery. We administered a questionnaire to evaluate the degree of LARS. In addition, we examined clinical characteristics with univariate and multivariate analysis to identify predictive factors for major LARS. Finally, we divided the obtained data into a learning set and a validation set. We constructed a predictive model for major LARS using the learning set and assessed the predictive accuracy of the validation set. RESULTS: We reviewed 160 patients with rectal cancer and divided them into a learning set (n = 115) and a validation set (n = 45). Univariate and multivariate analyses in the learning set showed that male (odds ratio [OR]: 2.88, 95% confidence interval [95%CI] 1.11-8.09, p = 0.03), age < 75 years (OR: 5.87, 95%CI 1.14-47.25, p = 0.03) and tumors located < 8.5 cm from the AV (OR: 7.20, 95%CI 2.86-19.49, p < 0.01) were significantly related to major LARS. A prediction model based on the patients in the learning set was well-calibrated. CONCLUSIONS: We found that sex, age, and tumor location were independent predictors of major LARS in Japanese patients that underwent rectal cancer surgery. Our predictive model for major LARS could aid medical staff in educating and treating patients with rectal cancer before and after surgery.

Impact of aspirin discontinuation on thrombotic complications in laparoscopic colorectal cancer surgery.

BACKGROUND: The number of patients taking antiplatelet therapy is increasing. However, there is no definitive guideline for the perioperative management of antiplatelet therapy. Conventionally, the discontinuation of antiplatelet drugs has been the basic treatment as perioperative management. Therefore, we investigated the risk of discontinuing aspirin concerning thrombotic complications in laparoscopic colorectal cancer surgery. METHODS: Between January 2015 and December 2019, a total of 729 patients underwent laparoscopic colorectal cancer surgery in Toyonaka Municipal Hospital. Sixty-four patients taking antithrombotic drugs aside from aspirin were excluded from this study; the remaining 665 patients were considered eligible and divided into three groups. The patients not taking aspirin were classified as the "Control group" (n = 588). Among the patients taking aspirin, those who continued preoperative aspirin were classified as the "Aspirin group" (n = 30), and those who discontinued preoperative aspirin were classified as the "No-aspirin group" (n = 47). The Aspirin, No-aspirin, and Control groups were compared retrospectively. RESULT: Among the 3 groups, there were no significant difference in operative time (p = 0.14), bleeding volume (p = 0.63), or postoperative hospital stay (p = 0.06). Assessing the postoperative complication, bleeding complications were significantly more frequent in the Aspirin group (p < 0.01), although those complications were all Clavien-Dindo grade II. In contrast, thrombotic complications were significantly more frequent in the No-aspirin group (p < 0.01). Note that those complications were all Clavien-Dindo Grade III/IV. This result suggested that discontinuing aspirin increased the risk of severe thrombotic complication. CONCLUSION: Discontinuation of aspirin as perioperative management in laparoscopic colorectal cancer surgery increased the risk of severe thrombotic complications.

Fecal Stream Diversion Changes Intestinal Environment, Modulates Mucosal Barrier, and Attenuates Inflammatory Cells in Crohn's Disease.

BACKGROUND: The intestinal environment plays important roles in mucosal barrier homeostasis and intestinal inflammation, as clarified in studies using experimental animals but not in humans. AIMS: We investigated whether environmental changes in the fecal stream cause phenotypic changes in the human mucosal barrier. METHODS: We obtained human ileal samples after fecal stream diversions in patients with rectal cancer or Crohn's disease. We investigated the bacterial load and diversity in the human defunctioned ileum, defined as the anal side of the ileum relative to the ileostomy. We also examined the epithelium and lamina propria cell phenotypes in the defunctioned ileum. RESULTS: After fecal stream diversion, bacterial loads decreased significantly in the defunctioned ileum. Based on the Chao1, Shannon, and observed species indices, the diversity of mucosa-associated microbiota was lower in the defunctioned ileum than in the functional ileum. Moreover, the healthy defunctioned ileum showed reductions in villous height, goblet cell numbers, and Ki-67+ cell numbers. Additionally, interferon-γ+, interleukin-17+, and immunoglobulin A+ cell abundance in the lamina propria decreased. After the intestinal environment was restored with an ileostomy closure, the impaired ileal homeostasis recovered. The defunctioned ileum samples from patients with Crohn's disease also showed reductions in interferon-γ+ and interleukin-17+ cell numbers. CONCLUSIONS: Fecal stream diversion reduced the abundance and diversity of intestinal bacteria. It also altered the intestinal mucosal barrier, similar to the alterations observed in germ-free animals. In patients with Crohn's disease, Th1 and Th17 cell numbers were attenuated, which suggests that the host-microbiome interaction is important in disease pathogenesis.

Locally advanced rectal cancer receiving total neoadjuvant therapy combined with nivolumab: a case report and literature review.

BACKGROUND: The standard treatment for locally advanced rectal cancer (LARC) is preoperative chemoradiotherapy (CRT) followed by surgery and adjuvant chemotherapy. However, it has been suggested that intensification of neoadjuvant treatment with polychemotherapy in addition to CRT instead of as an adjuvant chemotherapy is better tolerated and associated with a higher pathological complete response (pCR) rate. This concept is known as total neoadjuvant therapy (TNT). Recently, the addition of immunotherapy to preoperative CRT has been reported to be useful in LARC patients with mismatch-repair-deficiency and high levels of microsatellite instability (MSI-H), but there are no reports showing the therapeutic effect of nivolumab in combination with TNT. CASE PRESENTATION: A 23-year-old man had frequent diarrhea. Preoperative examination revealed two adenocarcinomas in the rectum. His maternal grandmother had a rectal cancer patient who developed the disease at age 70s. The larger tumor was located at the peritoneal reflection, and its anterior border close to the prostate (<1 mm); there were eight enlarged pararectal lymph nodes. Considering the size and depth of the tumor, it was judged that radical resection with sufficient margins would be difficult. Therefore, it was decided that TNT would be performed. At first, CAPOX (capecitabine and L-OHP) was administered, followed by preoperative CRT (RT:50.4 Gy and capecitabine). During this period, genetic testing diagnosed this patient as MSI-H, so additional nivolumab was administered after CRT. Colonoscopy revealed that the larger tumor was no longer detectable, so robot-assisted intersphincteric resection and bilateral lateral lymph node dissection was performed. The diagnosis of pCR was made for the larger tumor and partial response was achieved for the smaller tumor, and no lymph node metastasis was found. Major complications were not observed and the patient was discharged on the 14th day after surgery. He was followed up without adjuvant chemotherapy and is alive and recurrence-free after 9 months. CONCLUSION: A case of LARC with MSI-H was treated with TNT with nivolumab, resulting in pCR and complete radical resection. This result suggests that nivolumab in addition to TNT can be an option as a preoperative strategy for LARC with MSI-H.

The prediction of postoperative anorectal dysfunction after low anterior resection for lower rectal cancer by measuring the volume of defecation-related muscles.

PURPOSE: Approximately 90% of patients are thought to develop bowel dysfunction after low anterior resection (LAR). Although some prognostic factors have been reported, the volumes of defecation-related muscles have not been examined. This retrospective study investigated the association between the preoperative volume of defecation-related muscles and major LARS. METHODS: Forty-six patients who underwent LAR for rectal cancer between 2013 and 2020 in our institution were analyzed. They had no local residual tumor or local recurrence at the time of the study and no problems with their defecation function pre-operatively. Defecation-related muscle volume measurements were made before surgery, and the patients answered a low anterior resection syndrome (LARS) score questionnaire after surgery. The muscle volume was adjusted by the patient's height squared. RESULTS: Twenty-seven patients (58.7%) developed major LARS. In the univariate analysis, sex, lateral lymph node dissection, and diverting ileostomy as well as muscle volume of the external anal sphincter, pubococcygeal + iliococcygeus muscle, and puborectal muscle were associated with major LARS. In a multivariate analysis, pubococcygeal + iliococcygeus muscle (< 5.96 ml/m2) was the only factor (p = 0.02). CONCLUSIONS: Measuring the volume of the defecation-related muscles may aid in predicting major LARS.

Postoperative pain management after concomitant sacrectomy for locally recurrent rectal cancer.

PURPOSE: To assess pain management in patients post-sacrectomy, focusing on opioid use, and to identify the factors associated with postoperative pain. METHODS: Patients who underwent resection of locally recurrent rectal cancer (LRRC) with concomitant sacrectomy at one of two hospitals between 2007 and 2020 were reviewed retrospectively. We examined the use of opioids preoperatively and postoperatively. Patients were classified into high and low sacrectomy groups based on the sacral bone resection level passing through the S3 vertebra. RESULTS: Sixty-four patients were enrolled. Opioid use was significantly higher in the high sacrectomy group than in the low sacrectomy group at all times assessed: on postoperative days 7, 14, 30, 90, 180, and 365. Opioid use 3 months after locally recurrent rectal cancer surgery was significantly higher in patients with local re-recurrence of the tumor than in those without re-recurrence (p < 0.05), and the median morphine-equivalent opioid use 3 months postoperatively was significantly higher in the high sacrectomy group (30 vs. 0 mg/day; p < 0.05). CONCLUSIONS: Opioid use after concomitant sacrectomy for LRRC was higher in the high sacrectomy group. Prolonged postoperative pain or increasing pain was associated with local recurrence.