Cell-free DNA (cfDNA) is derived from apoptosis/necrosis, active cellular secretion, and lysis of circulating cancer cells or micrometastases. In humans, cfDNA is widely used in cancer diagnosis, but veterinary research has yet to be actively conducted to establish it as a cancer biomarker. This retrospective study analyzed cfDNA levels in samples collected from dogs with neoplastic disease (n = 38), clinically ill dogs without neoplasia (n = 47), and healthy dogs (n = 35). cfDNA levels and clinical data were compared among groups, and prognostic analyses were performed within the neoplastic group. Furthermore, continual cfDNA measurements were performed during the chemotherapy of six dogs with lymphoma. Dogs with neoplasia showed significantly higher cfDNA concentrations than dogs without neoplasm, and the cfDNA oncentration in the lymphoid neoplasia group was significantly elevated among all neoplastic groups. Dogs with neoplasia and a plasma cfDNA concentration above 1,247.5 μg/L had shorter survival rates than those with levels below this threshold (26.5 vs. 86.1%, respectively, P < 0.05). In cases with complete remission in response to chemotherapy, the cfDNA concentration was significantly decreased compared with the first visit, whereas the cfDNA concentration was increased in cases with disease progression or death. Interestingly, a significant correlation was found between lymph node diameter and cfDNA concentration in dogs with multicentric lymphoma (R² = 0.26, P < 0.01). These data suggest that changes in cfDNA concentration could be used as a diagnostic biomarker for canine neoplasia. Furthermore, increased plasma DNA levels might be associated with shorter survival time, and cfDNA concentrations may reflect the response to chemotherapy.

Background: The association of gut microbiota with cancer etiology and prognosis has been demonstrated in humans and rodents but has not been studied in dogs with different types of tumors. Hypothesis/Objectives: To analyze microbiome composition according to tumor progression based on metastasis, recurrence, and therapeutic response in canine tumors. Animals: Thirty-two client-owned dogs were divided into 3 groups: healthy (n = 9), with lymphoma (n = 12), with nonlymphoid tumors (n = 11). Methods: Retrospective case series included animals were divided into subgroups according to the nature and severity of their tumors. Feces were screened for the 16S rRNA gene. Results: Overall, alpha diversity was significantly reduced in dogs with tumors (n = 23; 12 lymphoid and 11 nonlymphoid) compared to healthy dogs (n = 9). Bacteroides had lower abundance in canine tumors at genus level. Staphylococcus showed significantly reduced abundance in dogs with aggressive tumor progression. Higher white blood cell (WBC) and neutrophil counts and lower hematocrit were significant in dogs with aggressive tumor. Spearman's rank correlation coefficient analysis revealed several measurements that showed moderate to strong correlations, including Coprococcus with total WBC count, neutrophil count, and hematocrit in the aggressive tumor group, and Saccharimonas with serum albumin and sodium concentration in all tumor dogs. Conclusion and Clinical Importance: The diversity of the gut microbiome was significantly reduced in dogs with tumors compared to healthy dogs. Correlations were found between changes in blood measurements and changes in microbiome composition in relation to paraneoplastic syndrome.

Bacillus amyloliquefaciens is a gram-positive bacterial species that is utilised as a probiotic in humans and animals. There are no reports of infective endocarditis (IE) in dogs. An 8-year-old, spayed, female Maltese presented with a 1-month history of fever, depression, weight loss, and hindlimb lameness. Laboratory test results indicated non-regenerative anaemia, neutrophilia, hyperglobulinemia, and proteinuria. Echocardiography revealed vegetation on the septal leaflet of the mitral valve and thromboemboli in the left atrium. Consecutive blood culture results revealed that the blood samples were consistently positive for Bacillus amyloliquefaciens, which is generally considered a probiotic bacterial species for animals. Broad-spectrum antibiotics (amoxicillin-clavulanic acid and cefotaxime) and anticoagulants (clopidogrel and rivaroxaban) were administered for 4 months. The clinical signs were responsive to antibiotic treatment. After 4 months, the dog was no longer febrile and the size of the thromboemboli in the left atrium had decreased. Bacteria were no longer isolated in blood cultures after antibiotic therapy. To the best of our knowledge, this is the first case report of canine IE caused by bactaeremic infection with Bacillus amyloliquefaciens.

Canine T-zone lymphoma (TZL) is a mature T-cell lymphoma in dogs. The diagnosis and sub-classification are impossible without biopsy or immunophenotyping by flow cytometry. An 11-year-old, spayed, female Golden Retriever presented with lymph node enlargement. Clinical examination was consistent with canine multicentric lymphoma. However, immunophenotyping revealed positive for CD3, CD4, CD5, CD8, CD21, TCRαβ, and MHCII but negative for CD34, CD45, CD79a, and TCRγδ. Histopathology revealed lymphocytes expanding to the cortex-preserving architecture and thinning of the nodal capsule, and CD3 positive but PAX-5 negative. Owing to the indolent nature of TZL, careful monitoring approach without clinical intervention was utilized.

Journal of Biomedical and Translational Research

Journal of Biomedical and Translational Research