Recurrence and survival in dogs with excised colorectal polyps: A retrospective study of 58 cases.

BACKGROUND: Compared to humans, colorectal polyps are relatively rare in dogs. Epidemiological and prognostic data remain accordingly sparse, although they could help veterinary clinicians in the management of these cases. OBJECTIVES: To report the epidemiological data of dogs with colorectal polyps and identify factors associated with recurrence and survival. ANIMALS: Fifty-eight client-owned dogs with colorectal polyps admitted to 7 veterinary hospitals (53 dogs from France, 5 dogs from Spain, and 4 dogs from Portugal) were included. METHODS: Retrospective multicentric cohort study. Medical records and long-term outcome of the dogs were reviewed. When available, histological samples were reassessed by 2 board-certified pathologists according to the revised Vienna classification (RVC). RESULTS: The West Highland White Terrier (WHWT) breed was significantly associated with the presence of colorectal polyps (OR: 20; 95% CI: 7.5-52; P < .001). The overall median time to recurrence was not reached after 2000 days. The overall estimated median survival time was 1640 days. WHWT breed and larger polyps were significantly associated with a shorter time of polyp recurrence after surgical removal (respectively, P = .05 and P = .01). CONCLUSIONS AND CLINICAL IMPORTANCE: The probability of recurrence of colorectal polyps in dogs is low, but increased in WHWTs and larger polyps, which might benefit from routine screening after removal. No effective predictors of polyp recurrence and survival were identified using the RVC.

[Multiple hyperplastic colon polyps in a cow]. / Multiple hyperplastische Kolonpolypen bei einem Rind.

INTRODUCTION: Reports on bovine colon polyps are rare. The present report demonstrates macro- and microscopically hyperplastic colon polyps of a seven-year-old German Simmental cow. Differential diagnoses (adenoma and adenocarcinoma) and aetiology are discussed. Even in cattle, intestinal polyps should be considered as a cause of intussusception.

INTRODUCTION: Les rapports concernant des polypes du colon chez les bovins sont rares. Le présent rapport fait état de polypes du côlon macro- et microscopiquement hyperplasiques chez une vache Simmental allemande de sept ans. Les diagnostics différentiels (adénome et adénocarcinome) et l'étiologie sont discutés. Même chez les bovins, les polypes intestinaux doivent être considérés comme une cause d'invagination.

Characterization of mucin gene expression and goblet cell proportion in inflammatory colorectal polyps in miniature dachshunds.

Hyperplastic goblet cells and abundant mucus are significant characteristics of inflammatory colorectal polyps (ICRPs) in miniature dachshunds. In this study, selected mucin gene expressions and goblet cell proportions were evaluated in miniature dachshunds with ICRPs and in healthy dogs. Mucin 2 (MUC2) gene expression was not significantly different among the groups, whereas mucin 5AC (MUC5AC) gene expression was significantly higher in the polypoid lesions than in healthy colonic mucosa. Although the percentage of goblet cells in the upper crypt regions did not significantly differ between the groups, that in the lower crypt regions was significantly decreased in polypoid lesions. In conclusion, increased MUC5AC gene expression and goblet cell proportion changes may be associated with the pathogenesis of ICRPs.

Gene expression of leucine-rich alpha-2 glycoprotein in the polypoid lesion of inflammatory colorectal polyps in miniature dachshunds.

Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are speculated to be a breed-specific inflammatory bowel disease (IBD). Leucine-rich alpha-2 glycoprotein (LRG) has been identified as a novel biomarker of human IBD. The aim of this study was to examine LRG gene expression in the polypoid lesions of ICRPs. Polypoid lesion specimens were collected from 24 MDs with ICRPs. Nonpolypoid colonic mucosa was collected from 18 MDs with ICRPs and 10 controls. The gene expression of LRG, interleukin (IL)-1ß, IL-6, tumor necrosis factor-α, and IL-22 was examined. The expression of LRG gene was significantly increased in the polypoid lesions of ICRPs and correlated with that of the four cytokines. In conclusion, the LRG gene was expressed within the polypoid lesions of ICRPs and might be associated with local cytokine expression.

Activities of matrix metalloproteinase-2, matrix metalloproteinase-9, and serine proteases in samples of the colorectal mucosa of Miniature Dachshunds with inflammatory colorectal polyps.

OBJECTIVE: To investigate the activities of gelatinases (matrix metalloproteinase [MMP]-2 and MMP-9) and serine proteases in the colorectal mucosa of Miniature Dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). ANIMALS: 15 MDs with ICRPs and 5 dogs with non-ICRP-related large bowel diarrhea (controls). PROCEDURES: Zymographic methods were used to evaluate the activities of MMP-2, MMP-9, latent forms of MMP-2 and MMP-9 (pro-MMP-2 and pro-MMP-9), and serine proteases in inflamed and noninflamed tissue samples from MDs with ICRPs and in noninflamed tissue samples from control dogs. The associations of serine protease activities with MMP-2 or MMP-9 activity were also analyzed. RESULTS: Activities of pro-MMP-2 and pro-MMP-9 were detected in most tissue samples, regardless of the tissue type, whereas activities of MMP-2 and MMP-9 were not detected in control tissue samples. In the inflamed tissue samples from MDs with ICRPs, the activities of MMP-2, pro-MMP-9, and MMP-9 were significantly higher than those in the noninflamed tissue samples from those dogs. Serine protease activities were significantly higher in the inflamed and noninflamed tissue samples from MDs with ICRP, compared with findings for control tissue samples. A weak correlation was detected between serine protease activities and MMP-9 activity. CONCLUSIONS AND CLINICAL RELEVANCE: Study results suggested that gelatinase and serine protease activities are upregulated in the colorectal mucosa of MDs with ICRPs, possibly contributing to the pathogenesis of this disease through the functions of these enzymes in degradation of extracellular matrix and promotion of inflammatory cell migration and inflammatory responses.

Comparison of the efficacy of cyclosporine and leflunomide in treating inflammatory colorectal polyps in miniature dachshunds.

Inflammatory colorectal polyps (ICRPs) are frequently observed in miniature dachshunds in Japan and treated by prednisolone and immunosuppressive drugs such as cyclosporine and leflunomide. The purpose of this retrospective study was to compare the treatment efficacy, such as response rate, response interval, recurrence rate, and adverse events between cyclosporine and leflunomide. While the response rates were significantly higher in dogs treated with leflunomide, no significant differences were observed in the response interval or recurrence rate. Two of the 11 dogs treated with leflunomide showed hematological or gastrointestinal adverse events, while no dog treated with cyclosporine showed any adverse events. A case-controlled prospective study to compare the treatment efficacy of leflunomide with that of cyclosporine should be conducted.

Distribution of regulatory T cells in inflammatory colorectal polyps of miniature dachshunds.

Inflammatory colorectal polyp (ICRP) is an emerging disease in Miniature Dachshunds (MDs). Animals with this disease exhibit multiple polyps with severe neutrophil infiltration that respond to immunosuppressive therapy. Macrophages in polypoid lesions have been described to play an important role in neutrophil infiltration in the lesion by producing IL-8. In contrast, IL-10, an anti-inflammatory cytokine, was also reported to be upregulated in polypoid lesions, but its significance in the pathogenesis of ICRP has not been clarified. Regulatory T cells (Tregs) are the main source of IL-10 production and contribute to the maintenance of intestinal homeostasis. Therefore, the objective of this research was to compare the distribution of Tregs in polypoid lesions of ICRPs and the association between the distribution and expression of pro- or anti-inflammatory cytokines. Tissue biopsy specimens of polypoid lesions were collected from 28 MDs with ICRP. Those of macroscopically non-polypoid colonic mucosa from 24 MDs with ICRPs and 21 control dogs were further included as controls. Real-time quantitative polymerase chain reaction was used to quantify gene expression of IL-1ß, IL-4, IL-6, IL-8, IL-10, IL-17, IL-22, IFN-γ, TNF-α, TGF-ß, and forkhead box protein P3 (Foxp3) in each tissue sample. The numbers of Foxp3-positive cells (Tregs) and ionized calcium binding adapter molecule 1 (Iba-1)-positive cells (macrophages) were determined by immunohistochemistry. The gene expression of IL-1ß, IL-6, IL-8, TNF-α, IFN-γ, IL-17, IL-10, TGF-ß, and Foxp3 was significantly upregulated in polypoid lesions relative to control levels. The numbers of Foxp3-positive Tregs and Iba-1-positive macrophages were significantly increased in polypoid lesions compared to those in the non-polypoid colonic mucosa of MDs with ICRPs and control dogs. The upregulation of IL-10 was moderately correlated with the distribution of Tregs in polypoid lesions from MDs with ICRPs. In addition, the relative upregulation of IL-1ß, IL-6, and IL-8 in polypoid lesions, compared to expression in non-polypoid colonic mucosa of MDs with ICRPs, was significantly greater than that of IL-10. These results indicate that increases in Treg numbers and anti-inflammatory cytokines in polypoid lesions comprise reactive changes in response to the inflammation, which warrants further investigation.

Histopathologic Features of Colorectal Adenoma and Adenocarcinoma Developing Within Inflammatory Polyps in Miniature Dachshunds.

Biopsy samples of colorectal polyps were collected and examined from 67 Miniature Dachshund dogs (including 35 cases with an additional biopsy). Histopathologic diagnoses of the initial biopsy samples were "inflammatory polyp" in 52 cases (78%), "adenoma" in 10 cases (15%), and "adenocarcinoma" in 5 cases (8%). Eight of 10 cases (80%) diagnosed as adenoma also had inflammatory polyp lesions in the same specimen. A second biopsy was performed in 25 cases (48%) initially diagnosed with inflammatory polyp. Pathologic diagnoses for the second biopsy were inflammatory polyp in 11 cases (44%), adenoma in 9 cases (36%), and adenocarcinoma in 5 cases (20%). The number of beta-catenin-positive nuclei in epithelial cells was significantly higher in adenoma (46%) and adenocarcinoma (75%) as compared with inflammatory polyp (6%). Normal epithelial cells and hyperplastic goblet cells in inflammatory polyps showed homogeneous positive cytoplasmic immunoreactivity for adenomatous polyposis coli (APC) antigen. However, APC expression was decreased in areas of intense nuclear beta-catenin expression in adenoma and adenocarcinoma lesions. Foci of cytokeratin 5/6-positive squamous cell-like neoplastic cells showed intense beta-catenin nuclear expression that was similar to squamous morules described in human colorectal tumors. The results of the present study suggest that the inflammatory polyp in Miniature Dachshunds is a progressive disease that may develop into adenoma and/or adenocarcinoma. In addition, immunohistochemical findings suggest that aberrations of APC and beta-catenin expression may be involved in tumor development within the inflammatory polyp lesions.

Combination Chlorambucil/Firocoxib or Chlorambucil/Prednisolone Treatment for Inflammatory Colorectal Polyps in Miniature Dachshunds.

Inflammatory colorectal polyps (ICRP), which are more commonly recognized in miniature dachshunds, are thought to represent an immune-mediated disease. This retrospective case series describes six miniature dachshunds with refractory ICRP, who were treated with chlorambucil (CLB) combined with firocoxib or prednisolone. Improvement in clinical manifestations was seen in five of the six dogs by the end of the study period; four were treated with CLB/firocoxib and one with CLB/prednisolone. One dog had nonregenerative anemia after 23 mo of treatment with CLB, but whether there was a causative relationship was unclear. No severe adverse events were observed during treatment in the remaining five dogs. CLB in combination with firocoxib or prednisolone appears to be an effective alternative treatment for ICRP in dogs. Further studies are needed to confirm the effectiveness and long-term complications of CLB treatment for ICRP in dogs.

Effects of probiotic bacteria on mucosal polyamines levels in dogs with IBD and colonic polyps: a preliminary study.

Spermine (SPM) and its precursor putrescine (PUT), regulated by ornithine decarboxylase (ODC) and diamino-oxidase (DAO), are polyamines required for cell growth and proliferation. Only a few studies have investigated the anti-inflammatory and tumour inhibitory properties of probiotics on mucosal polyamine levels. We investigated the effects of a high concentration multistrain probiotic for human use on colonic polyamine biosynthesis in dogs. Histological sections (inflammatory bowel disease, n=10; polyposis, n=5) were assessed after receiving 112 to 225×109 lyophilised bacteria daily for 60 days at baseline (T0) and 30 days after treatment end (T90). Histology scores, expression of PUT, SPM, ODC and DAO, and a clinical activity index (CIBDAI) were compared at T0 and T90. In polyps, cellular proliferation (Ki-67 expression), and apoptosis (caspase-3 protein expression) were also evaluated. After treatment, in inflammatory bowel disease significant decreases were observed for CIBDAI (P=0.006) and histology scores (P<0.001); PUT, SPM and ODC expression increased (P<0.01). In polyps, a significant decrease in polyamine levels, ODC activity, and Ki-67, and a significant increase in caspase-3 positivity and DAO expression (P=0.005) was noted. Our results suggest potential anti-proliferative and anti-inflammatory effects of the probiotic mixture in polyps and inflammation, associated with reduced mucosal infiltration and up-regulation of PUT, SPM, and ODC levels.

Stimulation of colorectal biopsies from miniature dachshunds with inflammatory colorectal polyps with toll-like receptor ligands: A pilot study.

Inflammatory colorectal polyps (ICRPs) in miniature dachshunds (MDs) are a possible novel form of breed-specific canine inflammatory bowel disease (IBD). In this pilot study, we investigated the effects of different Toll like receptor (TLR2, TLR4, TLR5 and TLR9) ligands on pro-inflammatory cytokines (IL-1ß, IL-6, IL-8 and TNF-α) gene expression in ex vivo-cultured colorectal samples from four MDs with ICRPs and four healthy MDs. At baseline, no significant difference in the mRNA expression levels of TLRs and pro-inflammatory cytokines was observed between cases and control MDs. After 4-h incubation, the relative ratios of TNF-α mRNA expression in the TLR2- or TLR4-stimulated colorectal samples, and IL-1ß mRNA expression in the TLR9-stimulated colorectal samples form cases showed higher tendency compared with healthy MDs (P<0.05), although statistically not significant. The results of this pilot study using small number of cases indicated that reactivity against TLR2, TLR4 or TLR9 ligand in the production of pro-inflammatory cytokines might be enhanced in the colorectal mucosa of ICRPs. Further research is needed to perform the functional analysis of TLRs in the sole cell population using intestinal epithelial primary culture and the mononuclear cells isolated from colonic mucosa.

Localization of Toll-like Receptor (TLR) 2 and TLR4 mRNA in the Colorectal Mucosa of Miniature Dachshunds with Inflammatory Colorectal Polyps.

Inflammatory colorectal polyps (ICRPs) are characterized by the formation of multiple or solitary polyps with marked neutrophil infiltration in the colorectal area, and are speculated to be a novel form of breed-specific canine idiopathic inflammatory bowel disease (IBD). In human IBD, toll-like receptor (TLR) 2 and TLR4 have been reported to be involved in the pathogenesis of the disease. The aim of this study was to evaluate the expression of TLR2 and TLR4 mRNA in the colorectal mucosa of dogs with ICRPs by in-situ hybridization using an RNAscope assay. Samples of inflamed colorectal mucosa (n = 5) and non-inflamed mucosa (n = 5) from miniature dachshunds (MDs) with ICRPs and colonic mucosa from healthy beagles (n = 5) were examined. TLR2 and TLR4 hybridization signals were localized to the colorectal epithelium, inflammatory cells and fibroblasts in the inflamed colorectal mucosa of affected dogs. The signals were significantly greater in inflamed colorectal epithelium compared with non-inflamed epithelium of MDs with ICRPs and healthy beagles (P <0.05). These results suggest that increased expression of TLR2 and TLR4 mRNA in the inflamed colorectal mucosa results from not only inflammatory cell infiltration, but also the upregulation of TLR2 and TLR4 mRNA in the colonic epithelium.

Expression of apical junction complex proteins in colorectal mucosa of miniature dachshunds with inflammatory colorectal polyps.

We examine the expression of tight junction and adherence junction proteins in the colorectal mucosa of miniature dachshunds (MDs) with inflammatory colorectal polyps (ICRPs). Colorectal mucosa samples were endoscopically obtained from 8 MDs with ICRPs and 8 control dogs for immunoblotting. Paraffin-embedded tissues of surgically resected inflamed lesions from another 5 MDs with ICRPs and full-thickness colorectal specimens from 5 healthy beagles were obtained for immunohistochemistry. The expression patterns of claudin-1, -2, -3, -4, -5, -7 and -8, E-cadherin and ß-catenin were analyzed in the non-inflamed mucosa and inflamed mucosa of ICRPs and colorectal mucosa of control dogs by immunoblotting. The localization of these proteins in the inflamed lesions was analyzed by immunohistochemistry. The expressions of each of claudin, E-cadherin and ß-catenin were not significantly different between control dogs and non-inflamed colonic mucosa from MDs with ICRPs. In contrast, only E-cadherin and ß-catenin were detected in the inflamed lesions of MDs with ICRPs. By immunohistochemistry, claudin-2, -3, -4, -5 and -7, E-cadherin and ß-catenin were expressed in the colorectal epithelium within the inflamed mucosa, but not in granulation tissue. Distributions of claudin-2, -3, -4, -5, and -7, E-cadherin and ß-catenin in the colonic epithelium were not different between MDs with ICRPs and control dogs. These results indicated that no significant alteration was detected in several tight junction or adherence junction proteins expression in the colorectal epithelium of ICRPs.

Efficacy of leflunomide for treatment of refractory inflammatory colorectal polyps in 15 Miniature Dachshunds.

Inflammatory colorectal polyp (ICRP), common in miniature dachshunds, presents with hematochezia, tenesmus and mucoid feces. Although an 80% response rate has been reported when treated with prednisolone and cyclosporine, effective treatment is needed for the remaining 20% of ICRP dogs. Leflunomide is an immunosuppressive drug reported as effective in several immune-mediated diseases. In the present study, we retrospectively evaluated the efficacy and adverse effects of leflunomide in 15 ICRP dogs that were refractory to treatment with prednisolone and cyclosporine. Treatment efficacy was assessed by endoscopy, clinical symptoms and rectal palpation. Adverse effects were determined by clinical symptoms and blood testing during follow-up. The leflunomide treatment response rate was 93.3%. The median dosage of leflunomide and the median response time were 3 mg/kg (range: 1.7-4.0 mg/kg) and 35 days (range: 20-119 days), respectively. Adverse effects observed included lethargy (3 dogs), anorexia (1 dog), respiratory symptoms (1 dog), leukocytopenia (2 dogs), thrombocytopenia (1 dog), anemia (1 dog) and liver enzyme elevation (8 dogs). Most of the adverse effects improved with symptomatic treatment and leflunomide discontinuation or dosage reduction. In conclusion, leflunomide treatment is effective in ICRP dogs refractory to treatment with prednisolone and cyclosporine. Because several adverse effects were observed, close monitoring is needed during leflunomide treatment follow-up.

Polymorphisms of nucleotide-binding oligomerization domain 2 (NOD2) gene in miniature dachshunds with inflammatory colorectal polyps.

Inflammatory colorectal polyps (ICRPs) frequently occur in miniature dachshunds (MDs) in Japan, typically form multiple polyps with severe neutrophil infiltration. ICRPs are speculated as a novel, breed-specific canine inflammatory bowel disease. Pattern recognition receptors (PRRs) play an important role in the differentiation of pathogens from commensal bacteria and food antigens, and polymorphisms of various PRRs have been shown to be associated with human and canine IBD. We recently reported that the reactivity of nucleotide-binding oligomerization domain 2 (NOD2), toll-like receptor (TLR) 1/2, TLR2, and TLR2/6 are greater in ICRP-affected MDs than that in controls. Therefore, this study was aimed to investigate single nucleotide polymorphisms (SNPs) of PRRs associated with ICRPs in MDs. Mutational analysis of canine NOD2, TLR1, TLR2, and TLR6 genes was performed with six ICRP-affected MDs, five control MDs, and five healthy beagles. The mutational analysis identified 13 non-synonymous SNPs in NOD2, TLR1, TLR2, and TLR6 genes, of which six SNPs in NOD2 exon 3 were further analyzed in an association study using 63 ICRP-affected MDs, 82 control MDs, and 237 control dogs of various breeds. Four of the SNPs (A1532G, T1573C, C1688G, and G1880A of the NOD2 gene) were in Hardy-Weinberg equilibrium and in complete linkage disequilibrium in MDs, and their minor allele frequencies were significantly lower in ICRP-affected MDs than in control MDs (0.016 vs. 0.140, P=0.0002). The calculated inheritance model was an additive model (odds ratio=0.10, 95% confidence interval=0.02-0.45, P=0.0001), which indicates that the haplotype with minor alleles in these SNPs (A, T, C, and G in A1532G, T1573C, C1688G, and G1880A) possess a protective effect regarding the development of ICRPs. However, these SNPs were not specific for MDs, although the minor allele frequencies of these SNPs in control MDs were significantly lower than in other breed dogs. These results suggest that the identified four SNPs (A1532G, T1573C, C1688G, and G1880A in the NOD2 gene) may play a role in the pathogenesis of ICRPs in MDs. Because the majority of MDs and other breed dogs do not have the protective alleles, their absence may not be a specific cause of ICRPs in MDs but rather contribute to the development of inflammation.

Functional analysis of pattern recognition receptors in miniature dachshunds with inflammatory colorectal polyps.

Inflammatory colorectal polyps (ICRPs) frequently occur in miniature dachshunds (MDs) in Japan. MDs with ICRPs develop multiple polyps with severe neutrophil infiltration that respond to immunosuppressive therapy. Therefore, ICRPs are thought to constitute a novel, breed-specific form of canine inflammatory bowel disease (IBD). Pattern recognition receptors (PRRs) play a key role in the distinction of pathogens from commensal bacteria and food antigens. Dysfunction resulting from genetic disorders of PRRs have been linked to human and canine IBD. Therefore, we analyzed the reactivity of PRRs in MDs with ICRPs. Twenty-six MDs with ICRPs and 16 control MDs were recruited. Peripheral blood-derived monocytes were obtained from each dog and then stimulated with PRR ligands for 6 and 24 hr; subsequently, messenger RNA (mRNA) expression levels and protein secretion of IL-1ß were quantified using quantitative real-time PCR and ELISA, respectively. The levels of IL-1ß mRNA and protein secretion after stimulation with a nucleotide-binding oligomerization domain 2 (NOD2) ligand were significantly greater in monocytes from ICRP-affected MDs than in those from control MDs. In addition, IL-1ß protein secretion induced by toll-like receptor (TLR) 1/2, TLR2 and TLR2/6 stimulation was also significantly greater in ICRP-affected MDs. These results suggest that reactivity against NOD2, TLR1/2, TLR2 and TLR2/6 signals is enhanced in ICRP-affected MDs and may play a role in the pathogenesis of ICRPs in MDs. Additional studies of the genetic background of these PRRs should be performed.

Inflammatory colorectal polyps in miniature Dachshunds frequently develop ventrally in the colorectal mucosa.

This study explored the hypothesis that inflammatory colorectal polyps (ICRPs) in miniature Dachshunds are more likely to occur ventrally in the colorectum. Angle-fixed colonoscopic images were collected from 11 miniature Dachshunds with ICRPs and randomly rotated. Macroscopic severity at 12 divided angles was scored by four veterinarians blinded to the rotation angle. Mean prevalence and severity scores of ICRPs were significantly higher ventrally than dorsally (P < 0.01).

Endoscopic mucosal resection and snare polypectomy for treatment of a colorectal polypoid adenoma in a dog.

CASE DESCRIPTION: An 11-year-old castrated male mixed-breed dog was examined for a 3-month history of hematochezia and tenesmus. Abdominal ultrasonography and rectal examination prior to referral had revealed a colorectal polyp, diagnosed as a benign colorectal polypoid adenoma after histologic examination of tissue samples. The patient was referred for treatment. CLINICAL FINDINGS: A 2-cm-diameter sessile polypoid mass was located approximately 6 cm orad to the anus in the right dorsolateral region of the descending colon just caudal to the pubis. There was no evidence of metastasis on thoracic radiography or abdominal ultrasonography. Results of a CBC and serum biochemical analysis were within reference limits. TREATMENT AND OUTCOME: Endoscopic mucosal resection (EMR) and snare electrocautery were used to resect the mass and a definitive histopathologic diagnosis of a sessile colorectal polypoid adenoma was made. A 9.9-mm gastroduodenoscope was used during colonoscopy to inspect the mass. To aid in EMR, a 25-gauge endoscopic injection needle was used to infuse sterile saline (0.9% NaCl) solution under the base of the polyp, into the submucosa to elevate the mucosa from the muscularis layer beneath the polyp prior to polypectomy. This was necessary because of the sessile, rather than pedunculated, base of the mass. The entire polyp was successfully removed with endoscopic guidance. The clinical signs of hematochezia and tenesmus resolved immediately, and serial rectal examinations were performed over the following 36 months with no palpable evidence of recurrence. CLINICAL RELEVANCE: The patient described in the present report underwent successful colonic EMR and snare polypectomy with no known evidence of mass recurrence during the following 36 months, suggesting that this minimally invasive procedure may be a valuable treatment option for sessile polyps. The advantage of this technique was that elevation of the mucosa via injection of saline solution improved visibility of the polyp and helped to separate the polyp base from the deeper submucosal colorectal tissue, making complete resection possible.

Markedly increased expression of interleukin-8 in the colorectal mucosa of inflammatory colorectal polyps in miniature dachshunds.

Inflammatory colorectal polyps (ICRPs) in miniature dachshunds were recently recognized as a major cause of large bowel diarrhea in this dog breed in Japan. ICRPs are characterized by the formation of multiple small polyps and/or space-occupying large polyps in the colorectal area and are thought to be a novel form of inflammatory bowel disease (IBD). To explore key mediators in the pathogenesis of ICRPs, we analyzed several pro-inflammatory cytokine (IL-1ß, IL-6, TNF-α, IL-8, IL-12p35, IL-12/23p40, and IL-23p19) mRNA expressions in colorectal polyps in ICRP dogs by quantitative PCR. Among these cytokines, IL-8 mRNA expression was markedly up-regulated in large polyps. To examine IL-8 protein expression, we analyzed IL-8 protein level and its location in colorectal mucosal specimens of ICRP dogs by ELISA and immunofluorescence microscopy. IL-8 protein was significantly increased in large polyps and serum in dogs with ICRPs compared to controls. By immunofluorescence microscopy, IL-8 was only localized in macrophages, but not in mucosal epithelial cells or neutrophils. IL-8-positive macrophages were significantly increased in large polyps compared to controls. These results suggest that IL-8 is produced mainly by macrophages and may induce neutrophil infiltration in the colorectal area of ICRP dogs.

Polypoid adenomas secondary to inflammatory colorectal polyps in 2 miniature dachshunds.

Two miniature dachshunds, a 7-year-old neutered male and an 8-year-old male, presented with chronic hematochezia and tenesmus. A solitary pedunculated or multiple diffuse colorectal polyps were identified by colonoscopy and resected by polypectomy. Inflammatory colorectal polyps (ICRPs) were diagnosed according to histopathological findings. Both cases were treated with immunosuppressive therapy, and the clinical signs were resolved, although the colorectal polyps remained to some extent. Several months after the initial diagnosis, both cases presented with recurrence of hematochezia and enlargement of the polyps. A second colonoscopic polypectomy was performed, and adenoma was diagnosed histopathologically in both cases. ICRPs are a nonneoplastic disease, but their long-term prognosis is unknown. Careful follow-up seems to be important, and repetitive biopsy is recommended when growth of polyps is identified in miniature dachshunds with ICRPs.