Risk factors for postoperative bleeding and early death in percutaneous endoscopic gastrostomy: A multicenter retrospective study.

BACKGROUND AND AIM: Comprehensive reports on the risk factors for bleeding and early death after percutaneous endoscopic gastrostomy (PEG) are limited. In this multicenter study, we retrospectively investigated the risk factors for bleeding and early death after PEG. METHODS: Patients (n = 1234) who underwent PEG between 2015 and 2020 at Osaka Medical and Pharmaceutical University and its affiliated hospitals (11 institutions in total) were evaluated for postoperative bleeding and early death (within 60 days) after PEG according to patient characteristics, construction method, medical history, medications, preoperative hematological findings, and perioperative adverse events. Multivariate logistic regression was performed to identify independent predictors of bleeding and early death after PEG. RESULTS: The risk factors for bleeding after PEG were PEG tube insertion using the modified introducer method (odds ratio [OR], 4.37; P = 0.0003), low platelet count (OR, 0.99; P = 0.014), antiplatelet therapy (OR, 2.11; P = 0.036), and heparinization (OR, 4.50; P = 0.007). Risk factors for early death were low body mass index (BMI) (OR, 0.89; P = 0.015), low serum albumin levels (OR, 0.50; P = 0.035), and comorbidity of active cancer (OR, 4.03; P < 0.0001). There was no significant association between bleeding and early death after PEG. CONCLUSIONS: We identified several risk factors for bleeding and early death after PEG. Risk factors for bleeding were PEG tube insertion using the modified introducer method, low platelet count, antiplatelet therapy, and heparinization. Risk factors for early death were low BMI, low serum albumin levels, and comorbidity of active cancer.

Evaluation of bowel preparation before colonoscopy by ultrasonographic monitoring of colonic fecal retention: a case series.

AIMS: While bowel preparation for colonoscopy is the key to successful examination, taking laxatives and showing stools to others causes both physical and mental distress to the patient. Thus, an alternative method to evaluation bowel preparation is necessary. In the current study, we studied the colonic fecal retention by ultrasonography (US) and examined the US finding which reflected completion of BP. MATERIAL AND METHODS: The subjects were outpatients who underwent colonoscopy. This report summarizes the ultrasonographic images of patients who underwent multiple US examinations for all five sites of the colon just before, during, and immediately after bowel preparation. According to the standard protocol, the patients took 2 L of polyethylene glycol-ascorbic acid as a laxative, which was discontinued when the nurse visually judged the stool to be clear. RESULTS: Seven patients in their 50s-80s, none of whom were unable to complete a colonoscopy due to residual feces were included in study. Following bowel preparation, the US images showed anechoic areas with haustration in four or all five areas of the colon. Three of the seven patients received low-dose laxatives (1.1-1.2 L); all three had watery stools in three or more colon areas and none of them were constipated at the time of taking 1 L of laxatives. CONCLUSIONS: Completion of bowel preparation can be assessed by the observation of anechoic areas with haustration in multiple colonic sites by ultrasonography.

Enhancement of O-linked N-acetylglucosamine modification promotes metastasis in patients with colorectal cancer and concurrent type 2 diabetes mellitus.

Reversible post-translational modification of serine and threonine residues by O-linked N-acetylglucosamine (O-GlcNAc), termed O-GlcNAcylation has been indicated to regulate the activities of a number of different proteins. Augmented O-GlcNAcylation contributes to the etiologies of type 2 diabetes mellitus (T2DM) and cancer. Moreover, diabetic conditions increase the risk of colorectal cancer. However, the effect of O-GlcNAcylation in patients with colorectal cancer and concurrent T2DM has not been elucidated. The current study evaluated the level of O-GlcNAcylation in patients with colorectal cancer with or without T2DM. Notably, O-GlcNAcylation levels were significantly higher in tissues from patients with T2DM compared with those in patients without T2DM, and higher in cancer tissues compared with corresponding adjacent tissues. O-GlcNAcylation and cancer stage were more strongly correlated in cancer tissues from patients with T2DM compared with those from patients without T2DM. Additionally, distant metastasis was significantly correlated with O-GlcNAcylation in cancer tissues from patients with T2DM. ß-catenin levels in colorectal cancer tissues were the highest in patients with advanced-stage cancer and concurrent T2DM. In SW480 human colon cancer cells, thiamet G (TMG) treatment and OGA silencing, which increased O-GlcNAcylation, significantly increased ß-catenin and SNAIL in high-glucose, but not during normal-glucose conditions. These data suggest that O-GlcNAcylation is closely associated with distant metastasis, most likely through upregulation of the ß-catenin/SNAIL signaling pathway in colorectal cancer patients with T2DM.

Autophagy deficiency exacerbates colitis through excessive oxidative stress and MAPK signaling pathway activation.

BACKGROUND AND AIM: Autophagy is an essential process involved in the pathogenesis of inflammatory bowel disease (IBD). Although there are many data showing the roles of autophagy in intestinal epithelial cells (IECs), the mechanisms involved remain to be fully elucidated. We investigated the influence of autophagy in IECs on gastrointestinal tract inflammation. METHODS: Mice with conditional knockout of Atg5 in IECs (Atg5flox/flox/villin-Cre mice) were subjected to dextran sulfate sodium (DSS)-induced colitis and analyzed for colitis susceptibility. Additionally, we used Atg5-silenced rat IECs (IEC6shAtg5 cells) for in vitro assays. RESULTS: Sensitivity to DSS markedly increased in Atg5flox/flox/villin-Cre mice compared to that in wild-type mice. In IEC6shAtg5 cells, apoptosis was enhanced, and cell viability significantly decreased compared to IEC-6 cells. The expression of proinflammatory cytokines increased upon suppression of autophagy. Furthermore, silencing of Atg5 was associated with inflammation of IECs, activation of the mitogen-activated protein kinase (MAPK) signaling pathway by the intracellular reactive oxygen species accumulation, and NF-κB p65 phosphorylation. CONCLUSIONS: Autophagy in IECs plays an essential role in the maintenance of intestinal homeostasis, and autophagy deficiency triggers inflammation. Development of methods targeting autophagy might be beneficial in the treatment of IBD.

Evaluation of the impact of linked color imaging for improving the visibility of colonic polyp.

Linked color imaging (LCI) is a novel endoscopic system used to increase color contrast. As LCI does not decrease luminal brightness, it may improve the detection of colonic neoplasms. However, the extent to which LCI improves the visibility of colonic polyps has not yet been determined. Between December 2016 and May 2017, patients who received total colonoscopy were consecutively recruited into this retrospective, single-center study. For each polyp identified, images obtained from white light (WL) imaging, blue laser imaging (BLI), and LCI of the same lesion and its surrounding mucosa were evaluated. The color differences (ΔE) between each lesion and its surrounding mucosa in non-magnified images were computed quantitatively using the CIELAB color space, which defines color perception according to colorimetric values, and compared among WL, BLI, LCI, and chromoendoscopy. The ΔE between the vessel and non-vessel areas in magnified images was also assessed. Of the 64 patients who were incorporated into this study, non-magnified and magnified (×80) images from 113 and 95 polyps, respectively, were assessed. The ΔE was intensified by LCI and chromoendoscopy compared with WL and BLI. The ΔE of neoplastic lesions was also intensified by LCI. In magnified images, BLI and LCI significantly increased the ΔE between the vessel and non-vessel areas compared with WL. Luminal brightness, indicated by L*, was not impaired by LCI; however, was reduced by BLI compared with WL and LCI. These results suggest that LCI enhanced the detection of colonic neoplasms without impairing luminal brightness. We propose the routine use of LCI for colonic polyp detection and BLI for magnifying observations of colonic polyps detected by LCI.

Cytomegalovirus infection in ulcerative colitis assessed by quantitative polymerase chain reaction: risk factors and effects of immunosuppressants.

We investigated the risk factors of and appropriate treatment for cytomegalovirus colitis in patients with ulcerative colitis, using quantitative polymerase chain reaction analysis to detect cytomegalovirus in the colonic mucosa. Between February 2013 and January 2017, patients with exacerbated ulcerative colitis who were admitted to our hospital were consecutively enrolled in this retrospective, single-center study. Patients were evaluated for cytomegalovirus using serology (antigenemia) and quantitative polymerase chain reaction analyses of the colonic mucosa, which were sampled during colonoscopy. Of 86 patients, 26 (30.2%) had positive quantitative polymerase chain reaction results for cytomegalovirus; only 4 were also positive for antigenemia. The ages of the cytomegalovirus DNA-positive patients were significantly higher than those of negative patients (p = 0.002). The mean endoscopic score of cytomegalovirus DNA-positive patients was significantly higher than that of cytomegalovirus DNA-negative patients. Treatment with combined immunosuppressants was associated with an increased risk of cytomegalovirus. Fourteen of 15 (93.3%) cytomegalovirus DNA-positive patients who were negative for antigenemia showed a clinical response to treatment with additional oral tacrolimus, without ganciclovir. cytomegalovirus reactivation in active ulcerative colitis is associated with age and combined immunosuppressant therapy. Because additional treatment with tacrolimus was effective, patients who are negative for antigenemia and cytomegalovirus DNA-positive colonic mucosa may recover without antiviral therapy.

Effect of egualen sodium hydrate on small-intestinal mucosal damage induced by low-dose aspirin: a prospective randomized clinical trial.

Low-dose aspirin, which is widely used to reduce the risk of cardio- and cerebrovascular thrombosis, often induces gastroenteropathy by increasing the permeability of the mucosa. However, therapeutic strategies for patients with low-dose aspirin-induced small intestinal injury have not been determined. We evaluated the preventative effect of egualen sodium hydrate, a gastro-protective agent that suppresses indomethacin-induced small-intestinal damage in rats, against small-intestinal mucosal damage induced by low-dose aspirin in healthy adult male volunteers. Participants were randomly allocated to receive aspirin 100 mg/kg daily (control group, n = 10) or aspirin 100 mg/kg plus egualen sodium 30 mg daily (egualen sodium group, n = 10). Small intestinal mucosal injury was evaluated by capsule endoscopy two weeks after initiation of drug administration. Fecal analyses (occult blood test, immunochemical test, transferrin measurement and calprotectin measurement) were carried out before and after treatment. Egualen sodium significantly suppressed the total number of small intestinal injuries detected by capsule endoscopy and the positive ratio for the fecal occult blood test. Daily use of 30 mg of egualen sodium showed a preventative effect on low-dose aspirin-induced small intestinal injury. Since acid suppression therapy was reported to exacerbate NSAIDs-induced enteropathy via dysbiosis, egualen sodium may be useful for patients treated with low-dose aspirin.

Evaluation of Alkylamine Modified Pt Nanoparticles as Oxygen Reduction Reaction Electrocatalyst for Fuel Cells via Electrochemical Impedance Spectroscopy.

Organically (octyl amine, OA) surface modified electrocatalyst (OA-Pt/CB) was studied for its oxygen reduction reaction (ORR) activity via dc methods and its charge and mass transfer properties were studied via electrochemical impedance spectroscopy (EIS). Comparison with a commercial catalyst (TEC10V30E) with similar Pt content was also carried out. In EIS, both the catalysts showed a single time-constant with an emerging high-frequency semicircle of very small diameter which was fitted using suitable equivalent circuits. The organically modified catalyst showed lower charge-transfer resistance and hence, low polarization resistance in high potential region as compared to the commercial catalyst. The dominance of kinetic processes was observed at 0.925-1.000 V, whereas domination of diffusion based processes was observed at lower potential region for the organic catalyst. No effect due to the presence of carbon was observed in the EIS spectra. Using the hydrodynamic method, higher current penetration depth was obtained for the organically modified catalyst at 1600 rpm. Exchange current density and Tafel slopes for both the electrocatalysts were calculated from the polarization resistance obtained from EIS which was in correlation with the results obtained from dc methods.

Intermittent fasting prompted recovery from dextran sulfate sodium-induced colitis in mice.

Fasting-refeeding in mice induces transient hyperproliferation of colonic epithelial cells, which is dependent on the lactate produced as a metabolite of commensal bacteria. We attempted to manipulate colonic epithelial cell turnover with intermittent fasting to prompt recovery from acute colitis. Acute colitis was induced in C57BL/6 mice by administration of dextran sulfate sodium in the drinking water for 5 days. From day 6, mice were fasted for 36 h and refed normal bait, glucose powder, or lactylated high-amylose starch. On day 9, colon tissues were subjected to analysis of histology and cytokine expression. The effect of lactate on the proliferation of colonocytes was assessed by enema in vivo and primary culture in vitro. Intermittent fasting resulted in restored colonic crypts and less expression of interleukin-1ß and interleukin-17 in the colon than in mice fed ad libitum. Administration of lactate in the colon at refeeding time by enema or by feeding lactylated high-amylose starch increased the number of regenerating crypts. Addition of lactate but not butyrate or acetate supported colony formation of colonocytes in vitro. In conclusion, intermittent fasting in the resolution phase of acute colitis resulted in better recovery of epithelial cells and reduced inflammation.

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, suppresses CXCL5 and SDF-1 and does not accelerate intestinal neoplasia formation in ApcMin/+ mice fed a high-fat diet.

The relationship between type 2 diabetes mellitus and intestinal neoplasia has been shown epidemiologically. A high-fat diet (HFD) is also known to promote insulin resistance, which is a risk factor for intestinal neoplasia. Dipeptidyl peptidase-4 (DPP-4) inhibitors are used in the clinic for the treatment of type 2 diabetes and also to prolong the effects of glucagon-like peptide-1 (GLP-1). However, since the intestinotrophic hormone GLP-2 and chemokines, such as CXCL5 and stromal cell-derived factor-1 (SDF-1), are also substrates of DPP-4, DPP-4 inhibitors may increase the risk of intestinal carcinogenesis. In this study, we evaluated the impact of a DPP-4 inhibitor on intestinal tumorigenesis in ApcMin/+ mice fed a HFD. Six-week-old male ApcMin/+ mice were randomized to either a normal diet (10 kcal% fat) group, a HFD (60 kcal% fat) group, or a HFD group treated with sitagliptin (STG). The mice were euthanized nine weeks after the start of treatment. Daily treatment with STG did not increase number of intestinal tumors in the HFD group; however, this increase was not statistically significant. The mucosal concentration of total GLP-2 was significantly increased in the HFD group. The chemokine protein array showed elevated plasma concentrations of CXCL5 and SDF-1 in the HFD group. The administration of STG significantly suppressed the levels of plasma CXCL5 and SDF-1 in mice fed a HFD. Since CXCL5 expression is increased in patients with type 2 diabetes, and GLP-2, CXCL5 and SDF-1 are associated with tumor progression, DPP-4 inhibition may have potential as an agent for decreasing the risk of cancer in obese or diabetic patients.

Multiple Mesenteric Panniculitis as a Complication of Sjögren's Syndrome Leading to Ileus.

Mesenteric panniculitis (MP) is a benign fibroinflammatory process characterized by the presence of fat necrosis, chronic inflammation and fibrosis in the mesentery. Although various causal factors, such as malignancy, chronic inflammatory conditions and autoimmune processes, have been identified, the precise etiology remains unknown. We herein report a rare case of MP accompanying Sjögren's syndrome in which a mass lesion and intestinal stenosis were observed simultaneously. This condition led to ileus, which was effectively treated using prednisolone.

The dipeptidyl peptidase-4 inhibitor sitagliptin suppresses mouse colon tumorigenesis in type 2 diabetic mice.

Patients with type 2 diabetes mellitus are known to have an increased risk of colorectal neoplasia. Dipeptidyl peptidase-4 (DPP-4) inhibitors have been used as a new therapeutic tool for type 2 diabetes. Since the substrates for DPP-4 include intestinotrophic hormones and chemokines such as GLP-2 and stromal cell-derived factor-1 (SDF-1), which are associated with tumor progression, DPP-4 inhibitors may increase the risk of colorectal tumors. However, the influence of DPP-4 inhibitors on colorectal neoplasia in patients with type 2 diabetes remains unknown. In the present study, we show that long-term administration of a DPP-4 inhibitor, sitagliptin (STG), suppressed colon carcinogenesis in leptin-deficient (ob/ob) C57BL/6J mice. Colonic mucosal concentrations of glucagon­like peptide-1 (GLP-1) and GLP-2 were significantly elevated in the ob/ob mice. However, mucosal GLP concentrations and the plasma level of SDF-1 were not affected by the administration of STG. Real­time PCR analysis revealed that colonic mucosal IL-6 mRNA expression, which was significantly upregulated in the ob/ob mice, was significantly suppressed by the long-term administration of STG. These results suggest that a DPP-4 inhibitor may suppress colon carcinogenesis in mice with type 2 diabetes in a GLP-independent manner. Since DPP-4 has multiple biological functions, further studies analyzing other factors related to colon carcinogenesis are needed.

Effect of adalimumab on an enterocutaneous fistula in patients with Crohn's disease: a case series.

Crohn's disease (CD) is characterized by transmural inflammation of the gastrointestinal tract, which predisposes patients to the formation of a fistula. The efficacy of adalimumab (ADA) for an enterocutaneous fistula remains unclear. In this report, we present a case series of 3 patients with enterocutaneous fistulizing CD treated with ADA. ADA treatment achieved sustained complete fistula closure in one patient. The other two cases, which failed to achieve fistula closure, had intestinal stenosis and were not receiving concomitant azathioprine. Combination therapy with ADA and azathioprine may be a useful option and an alternative to surgery for enterocutaneous fistulizing CD.

Effect of long-term proton pump inhibitor therapy and healing effect of irsogladine on nonsteroidal anti-inflammatory drug-induced small-intestinal lesions in healthy volunteers.

This study assessed time-course changes of the small intestinal lesions during long-term treatment with diclofenac sodium plus omeprazole and the effects of irsogladine on such lesions. Thirty two healthy volunteers were treated with diclofenac sodium (75 mg/day) plus omeprazole (10 mg/day) for 6 weeks, with irsogladine (4 mg/day) added from weeks 6 to 10 (Group A) or with diclofenac sodium plus irsogladine for 6 weeks (Group B). Five volunteers received diclofenac sodium plus omeprazole for 10 weeks (Group C). Subjects underwent capsule endoscopy at each time. In Group A, the number of lesions remarkably increased at week 2, but the worse was not found at week 6 compared with week 2, whereas no exacerbation of lesions was observed in Group B. Additional treatment with irsogladine from weeks 6 to 10 in Group A significantly decreased the number of lesions at weeks 10 compared with Group C. In Group C, no significant change in lesions was observed since weeks 2. In conclusions, a PPI did not prevent the occurrence of small intestinal damage. However such lesions were not aggravated since weeks 2. These suggested mucosal adaptation may occur in the small intestine. Irsogladine was effective in both preventing and healing such lesions.

The effects of a TGR5 agonist and a dipeptidyl peptidase IV inhibitor on dextran sulfate sodium-induced colitis in mice.

BACKGROUND AND AIM: Luminal nutrients stimulate enteroendocrine L cells to release gut hormones, including intestinotrophic glucagon-like peptide-2 (GLP-2). Because L cells express the bile acid receptor TGR5 and dipeptidyl peptidase-IV (DPPIV) rapidly degrades GLPs, we hypothesized that luminal TGR5 activation may attenuate intestinal injury via GLP-2 release, which is enhanced by DPPIV inhibition. METHODS: Intestinal injury was induced in mice by administration of dextran sulfate sodium (DSS) in drinking water (free access to water containing 5% DSS for 7 days). The selective TGR5 agonist betulinic acid (BTA) and the DPPIV inhibitor sitagliptin phosphate monohydrate (STG) were administered orally for 7 days. Male C57BL/6 mice (6-7 weeks old) were divided into five groups: normal control group, disease control group, BTA low group (drinking water containing 15 mg/L BTA), BTA high group (50 mg/L BTA), and BTA high + STG (3 mg/kg, i.g.) group. RESULTS: The selective TGR5 agonist BTA dose-dependently suppressed disease activity index and mRNA expression of the pro-inflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α in the colon. Nevertheless, STG administration had little additive effect on BTA-induced protection. Fibroblast activation protein mRNA expression, but not expression of other DPP family members, was increased in the colon of DSS-treated mice with increased mucosal DPPIV. Co-administration of the selective GLP-2 antagonist GLP-2 (3-33) reversed the effect of BTA. CONCLUSION: The selective TGR5 agonist BTA ameliorated DSS-induced colitis in mice via the GLP-2 pathway with no effect of DPPIV inhibition, suggesting that other DPP enzymatic activity is involved in GLP-2 degradation.

Combined treatment with dipeptidyl peptidase 4 (DPP4) inhibitor sitagliptin and elemental diets reduced indomethacin-induced intestinal injury in rats via the increase of mucosal glucagon-like peptide-2 concentration.

The gut incretin glucagon-like peptide-1 (GLP-1) and the intestinotropic hormone GLP-2 are released from enteroendocrine L cells in response to ingested nutrients. Treatment with an exogenous GLP-2 analogue increases intestinal villous mass and prevents intestinal injury. Since GLP-2 is rapidly degraded by dipeptidyl peptidase 4 (DPP4), DPP4 inhibition may be an effective treatment for intestinal ulcers. We measured mRNA expression and DPP enzymatic activity in intestinal segments. Mucosal DPP activity and GLP concentrations were measured after administration of the DPP4 inhibitor sitagliptin (STG). Small intestinal ulcers were induced by indomethacin (IM) injection. STG was given before IM treatment, or orally administered after IM treatment with or without an elemental diet (ED). DPP4 mRNA expression and enzymatic activity were high in the jejunum and ileum. STG dose-dependently suppressed ileal mucosal enzyme activity. Treatment with STG prior to IM reduced small intestinal ulcer scores. Combined treatment with STG and ED accelerated intestinal ulcer healing, accompanied by increased mucosal GLP-2 concentrations. The reduction of ulcers by ED and STG was reversed by co-administration of the GLP-2 receptor antagonist. DPP4 inhibition combined with luminal nutrients, which up-regulate mucosal concentrations of GLP-2, may be an effective therapy for the treatment of small intestinal ulcers.

Geranylgeranylacetone suppresses colitis­related mouse colon carcinogenesis.

Geranylgeranylacetone (GGA), an isoprenoid compound, is an anti-ulcer drug developed in Japan. GGA protects a variety of cells and tissues against numerous stresses via induction of heat shock protein (HSP) 70, and it has recently been reported to protect mice from experimental ulcerative colitis (UC). However, it is unknown whether GGA exhibits a preventive effect on UC-associated neoplasia. In the present study, we evaluated the preventive effects of GGA on colitis-related carcinogenesis in the mouse colon. Mice were administered 1,2-dimethylhydrazine (DMH) subcutaneously three times within a week, followed by 2 cycles of dextran sulfate sodium (DSS) (each cycle, 3% DSS for 7 days and then distilled water for 14 days) and they were sacrificed 28 days after the completion of the 2 cycles. The mice were divided into the following groups according to the diet received during the experiment: group A, which received a standard diet and served as a disease control; group B, which received a diet mixed with 0.25% GGA; group C, which received a diet mixed with 0.5% GGA; group D, which received a diet mixed with 1.0% GGA; group E, which received a diet mixed with 2.0% GGA; and group F, which received a diet containing no agents, including DSS and served as a normal control. The incidence of neoplasia was assessed. The expression of inducible nitric oxide synthase (iNOS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was also determined. In addition, the expression of HSP70 in the colon tissues was determined by immunohistochemistry and western blot analysis. The mean number of tumors was 16.6, 11.0, 9.4, 5.8, 5.4 and 0 in groups A-F, respectively. GGA significantly suppressed the occurrence of neoplasia in a dose-dependent manner. GGA treatment enhanced the expression of HSP70 and suppressed the oxidative damage in the background mucosa (i.e. lesion-free colon). These results suggest that GGA could be useful in the prevention of UC-associated neoplasia.

Oral tacrolimus for megacolon in patients with severe ulcerative colitis.

Toxic megacolon is an infrequent but life-threatening complication that occurs most commonly in patients with severe ulcerative colitis. Intravenous steroids are often recommended for patients with toxic megacolon secondary to ulcerative colitis. However, steroid dependency may mask the presence of intra-abdominal sepsis and is associated with refractoriness, during which cytomegalovirus reactivation may occur. In this report, we present two rare cases of megacolon accompanying pancolonic severe ulcerative colitis that were successfully treated with oral tacrolimus, including one steroid-naïve patient. In cases of ulcerative colitis with megacolon, treatment with oral tacrolimus is recommended, thereby avoiding steroid dependency and improving the long-term prognosis.

Chemokine receptor CCR8 is required for lipopolysaccharide-triggered cytokine production in mouse peritoneal macrophages.

Chemokine (C-C motif) receptor 8 (CCR8), the chemokine receptor for chemokine (C-C motif) ligand 1 (CCL1), is expressed in T-helper type-2 lymphocytes and peritoneal macrophages (PMφ) and is involved in various pathological conditions, including peritoneal adhesions. However, the role of CCR8 in inflammatory responses is not fully elucidated. To investigate the function of CCR8 in macrophages, we compared cytokine secretion from mouse PMφ or bone marrow-derived macrophages (BMMφ) stimulated with various Toll-like receptor (TLR) ligands in CCR8 deficient (CCR8-/-) and wild-type (WT) mice. We found that CCR8-/- PMφ demonstrated attenuated secretion of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 when stimulated with lipopolysaccharide (LPS). In particular, LPS-induced IL-10 production absolutely required CCR8. CCR8-dependent cytokine secretion was characteristic of PMφ but not BMMφ. To further investigate this result, we selected the small molecule compound R243 from a library of compounds with CCR8-antagonistic effects on CCL1-induced Ca2+ flux and CCL1-driven PMφ aggregation. Similar to CCR8-/- PMφ, R243 attenuated secretion of TNF-α, IL-6, and most strikingly IL-10 from WT PMφ, but not BMMφ. CCR8-/- PMφ and R243-treated WT PMφ both showed suppressed c-jun N-terminal kinase activity and nuclear factor-κB signaling after LPS treatment when compared with WT PMφ. A c-Jun signaling pathway inhibitor also produced an inhibitory effect on LPS-induced cytokine secretion that was similar to that of CCR8 deficiency or R243 treatment. As seen in CCR8-/- mice, administration of R243 attenuated peritoneal adhesions in vivo. R243 also prevented hapten-induced colitis. These results are indicative of cross talk between signaling pathways downstream of CCR8 and TLR-4 that induces cytokine production by PMφ. Through use of CCR8-/- mice and the new CCR8 inhibitor, R243, we identified a novel macrophage innate immune response pathway that involves a chemokine receptor.