Search

Background: Gallbladder mucocele (GBM) is a common disease in the canine gallbladder. Although the pathogenesis of GBM remains unclear, we recently reported that the excessive accumulation of mucin in the gallbladder is not a result of overproduction by gallbladder epithelial cells (GBECs). Hypothesis/Objectives: Changes in the function of GBECs other than the production of mucin are associated with the pathogenesis of GBM. We performed an RNA sequencing (RNA‐seq) analysis to comprehensively search for abnormalities in gene expression profiles of GBECs in dogs with GBM. Animals: Fifteen dogs with GBM and 8 dogs euthanized for reasons other than gallbladder disease were included. Methods: The GBECs were isolated from gallbladder tissues to extract RNA. The RNA‐seq analysis was performed using the samples from 3 GBM cases and 3 dogs with normal gallbladders, and the gene expression profiles were compared between the 2 groups. Differences in mRNA expression levels of the extracted differentially expressed genes (DEGs) were validated by quantitative reverse transcription polymerase chain reaction (RT‐qPCR) using samples of 15 GBM cases and 8 dogs with normal gallbladders. Results: Comparison of gene expression profiles by RNA‐seq extracted 367 DEGs, including ANO1, a chloride channel associated with changes in mucin morphology, and HTR4, which regulates the function of chloride channels. The ANO1 and HTR4 genes were confirmed to be downregulated in the GBM group by RT‐qPCR. Conclusions and Clinical Importance: Our results suggest that GBM may be associated with decreased function of chloride channels expressed in GBECs. [ABSTRACT FROM AUTHOR]

Although chemotherapy using CHOP-based protocol induces remission in most cases of canine multicentric high-grade B-cell lymphoma (mhBCL), some cases develop early relapse during the first induction protocol. In this study, we examined the gene expression profiles of canine mhBCL before chemotherapy and investigated their associations with early relapse during the first whole CHOP-based protocol. Twenty-five cases of mhBCL treated with CHOP-based protocol as first induction chemotherapy were included in this study. Sixteen cases completed the first whole CHOPbased protocol without relapse (S-group), and nine developed relapse during the chemotherapy (R-group). RNA-seq was performed on samples from neoplastic lymph nodes. Differentially expressed genes (DEGs) were extracted by the comparison of gene expression profiles between S- and R-groups, and the differences in the expression levels of these genes were validated by RTqPCR. Extracted 179 DEGs included the genes related to chemokine CC motif ligand, T-cell receptor signaling pathway, and PD-L1 expression and PD-1 checkpoint pathway. We focused on chemokine CC motif ligand, and CCL4 was confirmed to be significantly downregulated in the R-group (P=0.039). We also focused on the genes related to T-cell signaling pathway, and CD3E (P=0.039), ITK (P=0.023), and LAT (P=0.023) genes were confirmed to be significantly upregulated in the R-group. The current results suggest that both changes in tumor cells and the interactions between tumor cells and immune cells are associated with the efficacy of the chemotherapy for first remission induction. [ABSTRACT FROM AUTHOR]

Background: DNA methylation analysis might identify prognostic CpG sites in CHOP‐treated dogs with multicentric high‐grade B‐cell lymphoma (MHGL) with heterogenous prognosis. Objective: To identify prognostic CpG sites of MHGL through genome‐wide DNA methylation analysis with pyrosequencing validation. Animals: Test group: 24 dogs. Validation group: 100 dogs. All client‐owned dogs were diagnosed with MHGL and treated with CHOP chemotherapy. Methods: Cohort study. DNA was extracted from lymph node samples obtained via FNA. Genome‐wide DNA methylation analysis using Digital Restriction Enzyme Analysis of Methylation (DREAM) was performed on the test group to identify differentially methylated CpG sites (DMCs). Bisulfite pyrosequencing was used to measure methylation status of candidate DMCs in the validation group. Median survival times (MST) were analyzed using Kaplan‐Meier (log‐rank) product limit method. Results: DREAM analyzed 101 576 CpG sites. Hierarchical clustering of 16 262 CpG sites in test group identified group with better prognosis (MST = 55‐477 days vs 10‐301 days, P =.007). Volcano plot identified 1371 differentially methylated CpG sites (DMCs). DMC near the genes of FAM213A (DMC‐F) and PHLPP1 (DMC‐P) were selected as candidates. Bisulfite‐pyrosequencing performed on validation group showed group with methylation level of DMC‐F < 40% had favorable prognosis (MST = 11‐1072 days vs 8‐1792 days, P =.01), whereas group with the methylation level combination of DMC‐F < 40% plus DMC‐P < 10% had excellent prognosis (MST = 18‐1072 days vs 8‐1792 days, P =.009). Conclusion and Clinical Importance: Methylation status of prognostic CpG sites delineate canine MGHL cases with longer MST, providing owners with information on expectations of potential improved treatment outcomes. [ABSTRACT FROM AUTHOR]

Veterinary medicine has made tremendous progress for domestic dogs, which are irreplaceable family members enriching human life. Nevertheless, no adequate supply system exists for their blood products. This study examined the synthesis, structure, safety, and efficacy of poly(2-ethyl-2-oxazoline)-conjugated porcine serum albumin (POx-PSA) as an artificial plasma expander for dogs. The aqueous POx-PSA solution showed moderately high colloid osmotic pressure and good blood cell compatibility. Actually, lyophilized powder stored for 1 year can regenerate into a homogeneous solution. The circulation half-life of POx-PSA in rats was 2.1-fold longer than that of naked PSA. Rats produced neither anti-PSA IgG antibody nor anti-POx IgG antibody, which suggests excellent immunological stealth properties of POx-PSA. Complete resuscitation of hemorrhagic shock in rats was achieved soon after injection of POx-PSA solution. Serum biochemistry tests and histopathological observations indicated no abnormality in the related organs. When POx-PSA was administered to dogs intravenously, (i) no serum biochemical or hematological alteration was observed, also (ii) no overt deterioration of animal health was observed. These results indicate that POx-PSA has potential as an artificial plasma expander for dogs. [ABSTRACT FROM AUTHOR]

Background: Lymphoma with Mott cell change, or Mott cell lymphoma (MCL), is an uncommon variant of canine lymphoma. Because of its rare occurrence, there has been no comprehensive study describing the disease so far. Miniature dachshunds, a popular breed in Japan, sometimes experience MCL. Objectives: To investigate the clinical characteristics and outcomes of MCL in miniature dachshunds. Methods: Medical records were retrospectively reviewed to identify miniature dachshunds diagnosed with MCL and other types of lymphoma. Data on clinical and laboratory findings, treatments and outcomes were collected. Survival times were compared between miniature dachshunds with MCL and other types of lymphoma. Results: Of the 87 miniature dachshunds diagnosed with lymphoma, 9 (10%) had cytological characteristics of MCL. All 9 miniature dachshunds with MCL were categorised as having alimentary lymphoma (small and/or large intestine, 6 dogs; mesenteric lymph node, 3 dogs). The median age was 3.1 years (range, 2.0–9.4 years). All nine dogs were treated with chemotherapeutic protocols used for large cell lymphoma or alkylating agents such as melphalan or chlorambucil. The overall response rate to initial chemotherapy was 78%, and the median progression‐free survival was 105 days. Overall survival in these nine dogs ranged from 6 to >1513 days (median, 240 days), which was significantly longer than in 29 miniature dachshunds with alimentary large cell lymphoma other than MCL (median, 57 days; p = 0.0491). Conclusions: MCL in miniature dachshunds can be recognised as a peculiar type of B‐cell lymphoma occurring in relatively young dogs as an alimentary form and has a longer survival compared with typical alimentary large cell lymphoma. [ABSTRACT FROM AUTHOR]

DNA methylation is a comprehensively studied epigenetic modification and plays crucial roles in cancer development. In the present study, MethylCap‐seq was used to characterize the genome‐wide DNA methylation patterns in canine high‐grade B‐cell lymphoma (cHGBL). Canine methylated DNA fragments were captured and the MEDIUM‐HIGH and LOW fraction of methylated DNA was obtained based on variation in CpG methylation density. In the MEDIUM‐HIGH and LOW fraction, 2144 and 1987 cHGBL‐specific hypermethylated genes, respectively, were identified. Functional analysis highlighted pathways strongly related to oncogenesis. The relevant signaling pathways associated with neuronal system were also revealed, echoing recent novel findings that neurogenesis plays key roles in tumor establishment. In addition, 14 genes were hypermethylated in all the cHGBL cases but not in the healthy dogs. These genes might be potential signatures for tracing cHGBL, and some of them have been reported to play roles in various types of cancers. Further, the distinct methylation pattern of cHGBL showed a concordance with the clinical outcome, suggesting that aberrant epigenetic changes may influence tumor behavior. In summary, our study characterized genome‐wide DNA methylation patterns using MethylCap‐seq in cHGBL; the findings suggest that specific DNA hypermethylation holds promise for dissecting tumorigenesis and uncovering biomarkers for monitoring the progression of cHGBL. [ABSTRACT FROM AUTHOR]