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OBJECTIVE To review ordering patterns, positivity rates, and outcome data for a subset of consecutive samples submitted for a commercially available, blood-based multicancer early-detection liquid biopsy test for dogs using next-generation sequencing at 1 laboratory. SAMPLE 1,500 consecutively submitted blood samples from client-owned dogs with and without clinical suspicion and/or history of cancer for prospective liquid biopsy testing between December 28, 2021, and June 28, 2022. PROCEDURES We performed a retrospective observational study, reviewing data from 1,500 consecutive clinical samples submitted for liquid biopsy testing. Outcome data were obtained via medical record review, direct communication with the referring clinic, and/or a patient outcome survey through October 16, 2022. RESULTS Sixty-four percent (910/1,419) of reportable samples were submitted for cancer screening, 26% (366/1,419) for aid in diagnosis, and 10% (143/1,419) for other indications. The positivity rate was 25.4% (93/366) in aid-in-diagnosis patients and 4.5% (41/910) in screening patients. Outcome data were available for 33% (465/1,401) of patients, and outcomes were classifiable for 428 patients. The relative observed sensitivity was 61.5% (67/109) and specificity was 97.5% (311/319). The positive predictive value was 75.0% (21/28) for screening patients and 97.7% (43/44) for aid-in-diagnosis patients, and the time to diagnostic resolution following a positive result was < 2 weeks in most cases. CLINICAL RELEVANCE Liquid biopsy using next-generation sequencing represents a novel tool for noninvasive detection of cancer in dogs. Real-world clinical performance meets or exceeds expectations established in the test’s clinical validation study.

Age-related somatic genomic alterations in hematopoietic cell lines have been well characterized in humans; however, this phenomenon has not been well studied in other species. Next-generation sequencing-based liquid biopsy testing for cancer detection was recently developed for dogs and has been used to study the genomic profiles of blood samples from thousands of canine patients since 2021. In this study, 4870 client-owned dogs with and without a diagnosis or suspicion of cancer underwent liquid biopsy testing by this method. Copy number variants detected exclusively in genomic DNA derived from white blood cells (WBC gDNA-specific CNVs) were observed in 126 dogs (2.6%; 95% CI: 2.2–3.1); these copy number variants were absent from matched plasma cell-free DNA, and from tumor tissue in dogs with concurrent cancer. These findings were more common in older dogs and were persistent in WBC gDNA in over 70% of patients, with little to no change in the amplitude of the signal across longitudinal samples. Many of these alterations were observed at recurrent locations in the genome across subjects; the most common finding was a partial loss on CFA25, typically accompanied by a partial gain on the same chromosome. These early findings suggest that age-related somatic alterations may be present at an appreciable frequency in the general canine population. Further research is needed to determine the clinical significance of these findings.

Background Concurrent exocrine pancreatic dysfunction and decreased pancreatic organ size are common findings in various stages of human type 1 diabetes mellitus (DM). Exocrine pancreatic insufficiency (EPI) is incompletely described in diabetic dogs. Objective To compare canine trypsin-like immunoreactivity (cTLI) of diabetic dogs with that of healthy controls. A secondary aim was to evaluate the correlation between duration of DM and cTLI. Animals Thirty client-owned diabetic dogs and thirty client-owned control dogs. Methods Cross-sectional study. Diabetic and healthy control dogs were included if they had no clinical evidence of pancreatitis and if serum samples obtained after food was withheld were available. Serum cTLI was measured at a reference laboratory and compared between groups. Canine pancreatic lipase immunoreactivity (cPLI) was analyzed concurrently as an indicator of pancreatitis. Results The median cTLI concentration in all diabetic dogs (36.4 μg/L [range, 7.0-288 μg/L]) did not differ from control dogs (28.7 μg/L [range, 12.8-58.6 μg/L]) (P = .07; difference -7.8 μg/L [95% Confidence Interval (CI), -23.5 to 0.6 μg/L]). There was still no difference in cTLI between groups after exclusion of dogs with cPLI consistent with pancreatitis (n = 8 diabetic dogs). There was no correlation between cTLI and DM duration in all diabetic dogs (r = -0.07, [95% CI, -0.43 to 0.3], P = .7). Conclusions and clinical importance There was no evidence of EPI as evaluated using cTLI in this cohort of diabetic dogs, but concurrent increases in cPLI suggest cTLI might not be the optimal indicator of exocrine pancreatic dysfunction in dogs with DM.

Genotype-matched therapeutics have become widely adopted in the management of human cancers and can be guided by testing tumor tissue or cell-free DNA from plasma. OncoKB (Oncology Knowledge Base) is the first FDA-recognized database that contains information about these targetable somatic variants and corresponding therapeutic agents, including levels of evidence. Many of the human OncoKB variants have orthologs in the canine genome. This study was conducted to determine the feasibility of detecting these orthologs in dogs using liquid biopsy. This study involved two cohorts: The first was a cohort of 619 client-owned dogs with a variety of cancer diagnoses across all disease stages enrolled in a clinical validation study for a liquid biopsy test (herein the “research cohort”). All dogs had pre-treatment plasma samples collected at enrollment, and a subset of dogs also had matched tumor tissue collected. The second cohort comprised 457 client-owned dogs that had testing as part of the clinical deployment of the above-mentioned liquid biopsy test (herein the “clinical cohort”); 31% of these dogs had samples submitted as an aid in diagnosis (for dogs in which cancer was suspected clinically), and 69% had samples submitted for screening (in dogs with no a priori suspicion of cancer). Blood samples (and tumor samples, when available) were subjected to DNA extraction, proprietary library preparation, and next-generation sequencing. Sequencing data were analyzed using an internally developed bioinformatics pipeline to detect genomic alterations associated with the presence of cancer. Only canine orthologs of variants in the OncoKB database were evaluated in this study. Variants were called if they were observed in plasma at an allele frequency of at least 0.5%, with at least 6 unique supporting reads. Variants identified from plasma were subsequently genotyped in tissue without additional variant-level filtering. Analysis of plasma identified canine orthologs of OncoKB variants in ~8% of dogs in the research cohort, and ~4% of dogs in the clinical cohort. The higher percentage observed in the research cohort is likely due to the higher percentage of patients with confirmed cancer diagnosis. In the patients with an OncoKB ortholog in the research cohort, the dog had a cancer type that matched the human indication for the detected variant in 15% of cases. Of dogs in which an ortholog was identified in plasma, 44% had matched tumor tissue; and the variant observed in plasma was confirmed in tissue in >50% of these subjects. This study demonstrates the feasibility of detecting canine orthologs of targetable human cancer somatic variants in the blood of dogs using next-generation sequencing. Although it is currently unclear how human databases can be used to inform targeted treatment decisions in dogs, these findings may have relevance for comparative oncology studies and future precision therapeutics development for both species. Citation Format: Daniel S. Grosu, Ilya Chorny, Kristina M. Kruglyak, John A. Tynan, Susan C. Hicks, Todd A. Cohen, Allison L. O'Kell, Jill M. Rafalko, Jason Chibuk, Angela L. McCleary-Wheeler, Andi Flory, Dana W. Tsui. Liquid biopsy analysis reveals orthologs of actionable human cancer variants in dogs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3377.

Objectives To quantify anti-insulin antibodies in diabetic dogs treated with recombinant human insulin and to determine if insulin dosage or duration of treatment differed between anti-insulin antibody-positive and -negative diabetic dogs. Materials and methods Descriptive preliminary study using serum from 24 client-owned diabetic dogs treated for a minimum of 2 weeks with recombinant human insulin, and 24 client-owned healthy control dogs without diabetes. Sera were analysed by radioimmunoassay for anti-insulin antibodies. The proportion of antibody positive dogs was compared between groups by Fisher's exact test. Results Four diabetic (16.6%) and no control dogs were anti-insulin antibody positive. Clinical significance These results indicate that treatment with recombinant human insulin may induce anti-insulin antibodies in dogs, although this finding needs to be re-investigated in a larger study to investigate the impact of anti-insulin antibodies on glycaemic control.

The concept of age-related somatic alterations in the blood or bone marrow of humans, commonly referred to as clonal hematopoiesis of indeterminate potential (CHIP) or age-related clonal hematopoiesis (ARCH), has been well characterized. In humans, these abnormalities tend to be associated with advanced age, often exhibit consistent signal over time, and typically involve recurrent locations in the genome. Though these somatic alterations may be associated with an increased risk of cancer, they do not originate from the tumor when cancer is concurrently present in the body. This study describes early findings that suggest similar age-related somatic alterations may also be present in dogs. Recently, next-generation sequencing-based liquid biopsy testing was developed for cancer detection in dogs. The clinical validation of this test involved 1,100 cancer-diagnosed and presumably cancer-free client-owned dogs. The test has also been performed commercially in thousands of additional dogs since 2021. This recent ability to test large numbers of dogs using liquid biopsy affords an unprecedented opportunity to study the genomic profiles of a broad population of canine subjects. Blood samples from over three thousand dogs ranging in age from 1 to >15 years were used in this analysis. Cell-free DNA (cfDNA) was extracted from the plasma, and genomic DNA (gDNA) was extracted from the white blood cells present in the buffy coat. Both cfDNA and gDNA were analyzed using next-generation sequencing to identify somatic genomic alterations. In a subset of patients, tumor tissue was also available for evaluation. Recurrent variants (e.g., involving CFA6 and CFA25, among others) were identified in the gDNA of a small fraction of patients. These findings occurred more commonly in older dogs and were typically persistent in gDNA across subsequent timepoints (when available) with no significant change in signal over time. When a clinical cancer evaluation was pursued, the majority of dogs with these findings had no evidence of cancer. For those in which cancer was identified, and tumor tissue was available for testing, the genomic profiles of the tumor tissue and gDNA were uncorrelated in almost all cases, suggesting the concomitant presence of age-related somatic alterations was incidental to the patient’s cancer. Additionally, regardless of whether cancer was present in the patient, the variants detected in gDNA were typically not encountered in cfDNA. These findings may be early evidence for the existence of age-related somatic alterations in dogs that potentially resemble the phenomenon of CHIP/ARCH previously observed in humans. Additional studies are ongoing to determine if these incidental findings may represent a risk factor for cancer development in dogs. Citation Format: Dana W.Y. Tsui, Allison L. O'Kell, Todd A. Cohen, Katherine M. Lytle, Kristina M. Kruglyak, Maggie A. Marshall, Carlos A. Ruiz-Perez, John A. Tynan, Susan C. Hicks, Jill M. Rafalko, Daniel S. Grosu, Jason Chibuk, Ilya Chorny, Angela L. McCleary-Wheeler, Andi Flory. Incidental detection of age-related somatic genomic alterations in blood samples from dogs with and without cancer [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr A028.

INTRODUCTION: Dogs with naturally occurring diabetes mellitus represent a potential model for human type 1 diabetes, yet significant knowledge voids exist in terms of the pathogenic mechanisms underlying the canine disorder. Untargeted metabolomic studies from a limited number of diabetic dogs identified similarities to humans with the disease. OBJECTIVE: To expand and validate earlier metabolomic studies, identify metabolites that differ consistently between diabetic and healthy dogs, and address whether certain metabolites might serve as disease biomarkers. METHODS: Untargeted metabolomic analysis via liquid chromatography-mass spectrometry was performed on serum from diabetic (n=15) and control (n=15) dogs. Results were combined with those of our previously published studies using identical methods (12 diabetic and 12 control dogs) to identify metabolites consistently different between the groups in all 54 dogs. Thirty-two candidate biomarkers were quantified using targeted metabolomics. Biomarker concentrations were compared between the groups using multiple linear regression (corrected P

Background "Readability" of consent forms is vital to the informed consent process. The average human hospital consent form is written at a 10th grade reading level, whereas the average American adult reads at an 8th grade level. Limited information currently exists regarding the readability of veterinary general medical or clinical research consent forms. Hypothesis/objectives The goal of this study was to assess the readability of veterinary clinical trial consent forms from a group of veterinary referral centers recently involved in a working group focused on veterinary clinical trial review and consent. We hypothesized that consent forms would not be optimized for client comprehension and would be written above the National Institutes of Health-recommended 6th grade reading level. Animals None. Methods This was a prospective study assessing a convenience sample of veterinary clinical trial consent forms. Readability was assessed using 3 methods: the Flesch-Kincaid (F-K) Grade Level, Flesch Reading Ease Score (FRES), and the Readability Test Tool (RTT). Results were reported as mean (±SD) and compared across specialties. Results Fifty-three consent forms were evaluated. Mean FRES was 37.5 ± 6.0 (target 60 or higher). Mean F-K Grade Level was 13.0 ± 1.2 and mean RTT grade level was 12.75 ± 1.1 (target 6.0 or lower). There was substantial agreement between F-K and RTT grade level scores (intraclass correlation coefficient 0.8). Conclusions and clinical importance No form evaluated met current health literacy recommendations for readability. A simple and readily available F-K Microsoft-based approach for evaluating grade level was in substantial agreement with other methods, suggesting that this approach might be sufficient for use by clinicians and administrators drafting forms for future studies.

BackgroundEvidence for an autoimmune etiology in canine diabetes is inconsistent and could vary based on breed. Previous studies demonstrated that small percentages of diabetic dogs possess autoantibodies to antigens known to be important in human type 1 diabetes, but most efforts involved analysis of a wide variety of breeds. The objective of this study was to evaluate the presence of glutamic acid decarboxylase 65 (GAD65), insulinoma-associated protein 2 (IA-2), and zinc transporter 8 (ZnT8) autoantibodies in diabetic and non-diabetic Australian Terriers and Samoyeds, two breeds with comparatively high prevalence of diabetes, in the United States.ResultsThere was no significant difference in the proportion of samples considered positive for GAD65 or ZnT8 autoantibodies in either breed evaluated, or for IA-2 autoantibodies in Australian Terriers (p > 0.05). The proportion of IA-2 autoantibody positive samples was significantly higher in diabetic versus non-diabetic Samoyeds (p = 0.003), but substantial overlap was present between diabetic and non-diabetic groups.ConclusionsThe present study does not support GAD65, IA-2, or ZnT8 autoantibodies as markers of autoimmunity in canine diabetes in Samoyeds or Australian Terriers as measured using human antigen sandwich enzyme-linked immunosorbent (ELISA) assays. Future studies using canine specific assays as well as investigation for alternative markers of autoimmunity in these and other canine breeds are warranted.

While predominant as a disease entity, knowledge voids exist regarding the pathogenesis of canine diabetes. To test the hypothesis that diabetic dogs have similar metabolomic perturbations to humans with type 1 diabetes (T1D), we analyzed serum metabolomic profiles of breed- and body weight-matched, diabetic (n=6) and healthy (n=6) dogs by liquid chromatography-mass spectrometry (LC-MS) profiling. We report distinct clustering of diabetic and control groups based on heat map analysis of known and unknown metabolites. Random forest classification identified 5/6 dogs per group correctly with overall out of bag error rate=16.7%. Diabetic dogs demonstrated significant upregulation of glycolysis/gluconeogenesis intermediates (e.g., glucose/fructose, C6H12O6, keto-hexose, deoxy-hexose, (PAbbreviationsAA(amino acid)AAb(autoantibody)FA(fatty acid)HILIC(hydrophilic interaction liquid interaction chromatography)LC-MS(liquid chromatography mass spectrometry)OOB(out of bag)T1D(type 1 diabetes)T2D(type 2 diabetes)UF(University of Florida)

Despite decades of research in humans and mouse models of disease, substantial gaps remain in our understanding of pathogenic mechanisms underlying the development of type 1 diabetes. Furthermore, translation of therapies from preclinical efforts capable of delaying or halting β-cell destruction has been limited. Hence, a pressing need exists to identify alternative animal models that reflect human disease. Canine insulin deficiency diabetes is, in some cases, considered to follow autoimmune pathogenesis, similar to NOD mice and humans, characterized by hyperglycemia requiring lifelong exogenous insulin therapy. Also similar to human type 1 diabetes, the canonical canine disorder appears to be increasing in prevalence. Whereas islet architecture in rodents is distinctly different from humans, canine pancreatic endocrine cell distribution is more similar. Differences in breed susceptibility alongside associations with MHC and other canine immune response genes parallel that of different ethnic groups within the human population, a potential benefit over NOD mice. The impact of environment on disease development also favors canine over rodent models. Herein, we consider the potential for canine diabetes to provide valuable insights for human type 1 diabetes in terms of pancreatic histopathology, impairment of β-cell function and mass, islet inflammation (i.e., insulitis), and autoantibodies specific for β-cell antigens.

INTRODUCTION: We recently identified variances in serum metabolomic profiles between fasted diabetic and healthy dogs, some having similarities to those identified in human type 1 diabetes. OBJECTIVES: Compare untargeted metabolomic profiles in the non-fasted state. METHODS: Serum from non-fasted diabetic (n=6) and healthy control (n=6) dogs were analyzed by liquid chromatography-high resolution mass spectrometry. RESULTS: Clear clustering of metabolites between groups were observed, with multiple perturbations identified that were similar to those previously observed in fasted diabetic dogs. CONCLUSION: These findings further support the development of targeted assays capable of detecting metabolites that may be useful as biomarkers of canine diabetes.

Idiopathic stone formers often form calcium oxalate (CaOx) stones that are attached to calcium phosphate (CaP) deposits in the renal tissue, known as Randall’s plaques (RP). Plaques are suggested to originate in the renal tubular basement membrane and spread into the interstitial regions where collagen fibrils and vesicles become mineralized; if the epithelium is breached, the RP becomes overgrown with CaOx upon exposure to urine. We have developed a two-stage model system of CaP–CaOx composite stones, consisting of Stage (1) CaP mineralized plaque, followed by Stage (2) CaOx overgrowth into a stone. In our first paper in this series (Stage 1), osteopontin (and polyaspartate) were found to induce a non-classical mineralization of porcine kidney tissues, producing features that resemble RP. For the Stage 2 studies presented here, biomimetic RPs from Stage 1 were implanted into the bladders of rats. Hyperoxaluria was induced with ethylene glycol for comparison to controls (water). After 4 weeks, rats were sacrificed and the implants were analyzed using electron microscopy and X-ray microanalyses. Differences in crystal phase and morphologies based upon the macromolecules present in the biomimetic plaques suggest that the plaques have the capacity to modulate the crystallization reactions. As expected, mineral overgrowths on the implants switched from CaP (water) to CaOx (hyperoxaluric). The CaOx crystals were aggregated and mixed with organic material from the biomimetic RP, along with some amorphous and spherulitic CaOx near the “stone” surfaces, which seemed to have become compact and organized towards the periphery. This system was successful at inducing “stones” more similar to human idiopathic kidney stones than other published models.

Objective—To determine the effects of oral prednisone administration with or without ultralow-dose acetylsalicylic acid on coagulation parameters in healthy dogs and to assess intraindividual variation in thromboelastography results. Animals—14 healthy research dogs and 10 healthy client-owned dogs. Procedures—In a randomized controlled trial, research dogs underwent thromboelastography twice (3 days apart), and intraindividual variation in test results was calculated. Dogs were given prednisone (2 mg/kg/d, PO) plus acetylsalicylic acid (0.5 mg/kg/d, PO) or prednisone (2 mg/kg/d, PO) plus a placebo for 14 days, after which thromboelastography and other tests were repeated. Differences from preadministration (baseline) test results between and within groups were compared. In a separate trial, client-owned dogs also underwent thromboelastography twice 2 days apart to assess intraindividual variation in untreated dogs. Results—Intraindividual variation in thromboelastography results for research dogs was ≤ 10% for maximum amplitude (MA) and α angle. In the research dogs, MA and fibrinogen values significantly increased from baseline, whereas percentage lysis 30 minutes after attainment of the MA as well as antithrombin activity significantly decreased within each group. In the dogs that received prednisone plus a placebo, percentage lysis 60 minutes after attainment of the MA was significantly lower than at baseline. For all parameters for research dogs, there was no difference between groups for change from baseline. Intraindividual variation in findings for client-owned dogs was similar to the variation for research dogs. Conclusions and Clinical Relevance—Prednisone administration resulted in hypercoagulability in healthy dogs as indicated by an increase in MA and plasma fibrinogen concentration and a decrease in antithrombin activity. Concurrent ultralow-dose acetylsalicylic acid use had no effect on measured thromboelastography values. The high intraindividual variation in some thromboelastography parameters may preclude routine use of this technique in clinical practice.

A 3-year-old Labrador retriever was presented to the Western College of Veterinary Medicine for a tibial plateau levelling osteotomy. While performing a pre-operative epidural, thiopental was inadvertently administered into the epidural space. Treatment included epidural saline flushing and intravenous methylprednisolone sodium succinate. No neurologic deficits were detected.

BACKGROUND: Sterile nodular panniculitis (SNP) is an uncommon inflammatory condition of subcutaneous fat that can be idiopathic, but has also been associated with underlying conditions such as pancreatic disease or systemic lupus erythematosus (SLE). The pathogenesis and clinical course of the condition are not well understood. OBJECTIVES: To retrospectively review cases of SNP associated with systemic signs, concurrent disease, or both and characterize the clinical, laboratory, imaging, and histopathologic findings, treatment, and response to treatment. ANIMALS: Fourteen dogs with histologically confirmed SNP diagnosed between 1996 and 2008. METHODS: Retrospective study. RESULTS: Skin lesions were ulcerated or draining nodules in 9 dogs and nonulcerative subcutaneous nodules in 5. Most dogs had systemic signs, such as fever, inappetence, lethargy, and multiple lesions. Common clinicopathologic findings included neutrophilia with or without left shift, increased alkaline phosphatase activity, mild hypoglycemia, hypoalbuminemia, and proteinuria. Concurrent diseases included pancreatic disease, SLE, rheumatoid arthritis, polyarthritis, lymphoplasmacytic colitis, and hepatic disease. Dogs responded to immunosuppressive doses of corticosteroids when administered. Prognosis for recovery was related to the underlying disease process. CONCLUSIONS AND CLINICAL IMPORTANCE: SNP is not a single disease. Rather, it is a cutaneous marker of systemic disease in many cases. After thorough evaluation for concurrent disease and infectious causes, immunosuppressive treatment is often effective.