Outcomes of 434 dogs with non-steroidal anti-inflammatory drug toxicosis treated with fluid therapy, lipid emulsion, or therapeutic plasma exchange.

BACKGROUND: Traditional management of non-steroidal anti-inflammatory drug (NSAID) intoxication includes gastrointestinal decontamination, intravenous administration of fluids (IVF), and gastroprotection. Intravenous administration of lipid emulsion (ILE) and therapeutic plasma exchange (TPE) are popular novel therapeutic strategies. HYPOTHESIS: Compare outcomes of dogs treated with IVF, ILE, and TPE for NSAID intoxications and evaluate outcome predictors for drug subgroups. ANIMALS: Four hundred thirty-four dogs with NSAID intoxications (2015-2020). METHODS: Multicenter retrospective study of ibuprofen, carprofen, and naproxen intoxication. An ordinal outcome was defined as mild gastrointestinal, moderate kidney, or signs of severe central nervous system disease. RESULTS: Signs of neurological disease were overrepresented and acute kidney injury underrepresented in the TPE group among dogs exposed to kidney- or CNS-toxic doses (P = .05), though all TPE dogs with signs of neurological disease had evidence of neurotoxicity at presentation. Dogs treated with IVF had a higher maximal creatinine concentration (median, 1.1 mg/dL; range, 0.4-8.44 mg/dL) compared with IVF + ILE (median, 0.9 mg/dL; range, 0.4-6.2 mg/dL; P = .01). Increased maximum time to presentation (P < .001), higher baseline creatinine (P < .001) and PCV (P = .007), and absence of induced emesis (P < .001) were associated with greater clinical severity. Ibuprofen toxicosis was associated with more severe clinical signs compared with carprofen (P = .03). Overall survival rate was 99%. CONCLUSIONS AND CLINICAL IMPORTANCE: NSAID toxicosis generally carries an excellent prognosis in dogs. Despite similar outcomes of lower incidence of AKI in the TPE group, and slightly lower maximal creatinine concentration in dogs treated with ILE vs IVF alone, ILE and TPE should be considered in the management of severe NSAID toxicosis.

Doxorubicin for treatment of histiocytic sarcoma in dogs: 31 cases (2003-2017).

OBJECTIVE: To evaluate the efficacy of doxorubicin for treatment of histiocytic sarcoma (HS) in dogs, whether administered as the sole treatment or as an adjunct to surgery or radiation therapy. ANIMALS: 31 client-owned dogs with localized or disseminated HS examined between 2003 and 2017. PROCEDURES: Medical records were reviewed retrospectively, and data were collected. The Kaplan-Meier method was used to estimate time-to-progression from the date of first doxorubicin administration and survival time from initial diagnosis. Factors that could be associated with poorer outcomes with doxorubicin treatment were analyzed with log-rank tests. RESULTS: The objective response rate (ORR) was 26%. When stratified by disease status, dogs with localized and disseminated forms experienced 43% and 21% ORRs, respectively. Median time to progression after initiating doxorubicin treatment (n = 30 dogs) was 42 days. Median survival time from initial diagnosis to death (n = 29 dogs) was 169 days. Complete responses were obtained in only 2 dogs that had localized disease and received multimodality therapy. CLINICAL RELEVANCE: Benefits of doxorubicin administration in canine HS are modest, with a limited ORR and delay in tumor progression, and are comparable to effects attained with other single-agent regimens.

Outcomes of nonsteroidal anti-inflammatory drug toxicosis treated with therapeutic plasma exchange in 62 dogs.

BACKGROUND: Therapeutic plasma exchange (TPE) is gaining popularity for the management of nonsteroidal anti-inflammatory drug (NSAID) overdose in dogs. HYPOTHESIS/OBJECTIVES: Describe a population of dogs treated with TPE for NSAID overdose. ANIMALS: Sixty-two dogs with NSAID overdose treated with TPE. METHODS: Multicenter retrospective study of dogs treated with TPE for ibuprofen, carprofen, or naproxen overdose. RESULTS: The median dose of ibuprofen, carprofen or naproxen ingested was 533 mg/kg (range, 36-4857 mg/kg), 217 mg/kg (range, 88-625 mg/kg) and 138 mg/kg (range, 26-3000 mg/kg), respectively. Based on previously established toxic ranges for each NSAID, 2 (3.2%), 14 (22.6%), and 46 (74.2%) dogs ingested a gastrointestinal, renal, and neurological toxic dose, respectively. The median time between ingestion and presentation was 4 hours (range, 1-20 hours). The median number of plasma volumes processed was 1.6 (range, 0.4-2.2). The median TPE session duration was 2 hours (range, 1-4.5 hours). Circuit clotting developed during 8 (12.9%) sessions. Patient adverse events reported during 21 (33.8%) sessions consisted of urticaria (12.9%), asymptomatic hypocalcemia (9.6%), and hypotension (9.6%). The median duration of hospitalization was 2.25 days (range, 1-11 days). Sixty-one (98.4%) dogs survived to discharge, and none were rehospitalized. Thirty-one (91.1%) of the 34 dogs with at least 1 follow-up visit were not azotemic at the time of reevaluation. CONCLUSIONS AND CLINICAL IMPORTANCE: This population of dogs managed with TPE had excellent outcomes, even in cases of high NSAID dose ingestion. When TPE is available and the time frame is appropriate, this extracorporeal modality should be considered for the management of NSAID overdose.

Allogeneic peripheral blood haematopoietic stem cell transplantation for the treatment of dogs with high-grade B-cell lymphoma.

Autologous peripheral blood haematopoietic stem cell transplantation (HCT) cures 33%-40% of dogs with high-grade B-cell lymphoma. We hypothesized, based on human allogeneic bone marrow transplantation literature, that transplanting dogs using canine donor leukocyte-matched CD34+ cells would lead to fewer relapses and increased cure rates. We retrospectively reviewed medical records of dogs diagnosed with high-grade B-cell lymphoma who received an identical allogeneic HCT. A total of 15 dogs transplanted at four facilities were identified. Five of fifteen dogs relapsed before transplant. The mean number of donor CD34+ cells/kg harvested and infused into recipient dogs was 8.0 × 106 /kg (range: 2.08 × 106 /kg-2.9 × 107 /kg). The median disease-free interval and overall survival of all dogs was 1095 days (range: 9-2920 days) and 1115 days (range: 9-2920 days), respectively. Two of five dogs, not in remission at transplant, died in the hospital. The median disease-free interval and overall survival of the remaining three dogs was 25 days (range: 15-250 days) and 1100 days (range: 66-1902 days), respectively. The median disease-free interval and overall survival of the 10 dogs who had not relapsed was 1235 days (range: 19-2920 days) and 1235 days (range: 19-2920 days), respectively. One dog died soon after discharge of presumed gastric-dilatation-volvulus. Eight of nine remaining dogs lived >4 yrs post-alloHCT, leading to a cure rate of 89%. Acute graft versus host disease was seen in three dogs. These results suggest that allogeneic HCT can cure ~50% more dogs than those treated with autologous HCT.

Centrifugal therapeutic plasma exchange in dogs with immune-mediated hemolytic anemia (2016-2018): 7 cases.

OBJECTIVE: To describe the technique of centrifugal therapeutic plasma exchange (cTPE) in dogs diagnosed with immune-mediated hemolytic anemia (IMHA) and summarize the outcome of the procedure. DESIGN: Retrospective review of cTPE performed at North Carolina State University from 2016 to 2018, through a search of the institutional database for cTPE and IMHA. SETTING: University teaching hospital. ANIMALS: Seven dogs with confirmed IMHA were presented to a university teaching hospital ICU for cTPE. Six dogs were not responsive to standard medical management with immunosuppressive agents, while 1 dog presented before immunosuppressive agents were begun. INTERVENTIONS: All dogs underwent multiple cTPE procedures using 1 of 2 commercially available apheresis systems. MEASUREMENTS AND MAIN RESULTS: At presentation, the median HCT was 0.15 L/L (15.7%) (range, 0.10-0.19 L/L [10.3%-19%]) and the median total serum bilirubin was 32.5 mmol/L (1.9 mg/dl) (range, 15.4-597 mmol/L [0.9-34.9 mg/dl]). The median number of transfusions before cTPE was 1 (range, 1-4), with a median total of infused RBCs of 12.9 ml/kg (range, 8.8-37 ml/kg). cTPE with an exchange of ≥4 times total plasma volumes was used to decrease the level of circulating autoreactive antibodies. The median total plasma volumes exchanged was 4.5 times (range, 2.5-6.5 times) over 2-4 procedures. Anticoagulation was performed using a combination of systemic heparinization and regional citrate in all dogs. Six of 7 dogs (85.7%) were discharged from the hospital and were alive 90 days after discharge. One dog (14%) did not respond to cTPE (∼6.5 times total plasma volume exchanged) and was euthanized. CONCLUSIONS: cTPE is a feasible and relatively safe bridging treatment option for the management of canine IMHA.

A Retrospective Analysis: Autologous Peripheral Blood Hematopoietic Stem Cell Transplant Combined With Adoptive T-Cell Therapy for the Treatment of High-Grade B-Cell Lymphoma in Ten Dogs.

In humans, a type of cellular immunotherapy, called adoptive T cell transfer (ACT), can elicit curative responses against hematological malignancies and melanoma. ACT using ex vivo expanded peripheral blood T-cells after multiagent chemotherapy enhances tumor-free survival of dogs with B-cell lymphoma (LSA). Since 2008, our group has been performing autologous peripheral blood hematopoietic stem cell transplants (autoPBHSCT) for the treatment of canine high-grade B-cell LSA, although relapse of residual disease is a common cause of reduced survival in ~70% of treated dogs. We reasoned that a more aggressive treatment protocol combining CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy, autoPBHSCT, and ACT to treat 10 dogs with B-cell LSA could lead to better outcomes when compared to dogs treated with CHOP chemotherapy and autoPBHSCT alone. Using this protocol, once dogs achieved complete hematologic reconstitution post-autoPBHSCT, CD3+ CD8+ and CD3+CD4+ T-cells were expanded from the peripheral blood at a commercial laboratory. Two to four ACT infusions were given to each dog, with a total of 23 infusions given. Infusions were administered with no complications or adverse events. The median cell dose for all infusions was 5.62 x 106 cells/kg (range: 2.59 x 106-8.55 x 106 cells/kg). 4/10 (40%) of dogs were cured of their disease (defined as disease-free for ≥2 years post-autoPBHSCT). Our results confirm that the autoPBHSCT protocol did not hinder the in vitro expansion of autologous peripheral blood T-cells and that the final product could be administered safely, with no adverse events recorded. Finally, since only ten dogs were treated, our results can only suggest that the administration of ACT to dogs after multiagent chemotherapy and autoPHSCT did not lead to a statistically significant increase in median disease-free interval and overall survival when compared to dogs who received CHOP chemotherapy and autoPHSCT alone.

Adjuvant Sirolimus Does Not Improve Outcome in Pet Dogs Receiving Standard-of-Care Therapy for Appendicular Osteosarcoma: A Prospective, Randomized Trial of 324 Dogs.

PURPOSE: The mTOR pathway has been identified as a key nutrient signaling hub that participates in metastatic progression of high-grade osteosarcoma. Inhibition of mTOR signaling is biologically achievable with sirolimus, and might slow the outgrowth of distant metastases. In this study, pet dogs with appendicular osteosarcoma were leveraged as high-value biologic models for pediatric osteosarcoma, to assess mTOR inhibition as a therapeutic strategy for attenuating metastatic disease progression. PATIENTS AND METHODS: A total of 324 pet dogs diagnosed with treatment-naïve appendicular osteosarcoma were randomized into a two-arm, multicenter, parallel superiority trial whereby dogs received amputation of the affected limb, followed by adjuvant carboplatin chemotherapy ± oral sirolimus therapy. The primary outcome measure was disease-free interval (DFI), as assessed by serial physical and radiologic detection of emergent macroscopic metastases; secondary outcomes included overall 1- and 2-year survival rates, and sirolimus pharmacokinetic variables and their correlative relationship to adverse events and clinical outcomes. RESULTS: There was no significant difference in the median DFI or overall survival between the two arms of this trial; the median DFI and survival for standard-of-care (SOC; defined as amputation and carboplatin therapy) dogs was 180 days [95% confidence interval (CI), 144-237] and 282 days (95% CI, 224-383) and for SOC + sirolimus dogs, it was 204 days (95% CI, 157-217) and 280 days (95% CI, 252-332), respectively. CONCLUSIONS: In a population of pet dogs nongenomically segmented for predicted mTOR inhibition response, sequentially administered adjuvant sirolimus, although well tolerated when added to a backbone of therapy, did not extend DFI or survival in dogs with appendicular osteosarcoma.

Clinical Application of Apheresis in Very Small Dogs Weighing <8 kg to Pediatric Patients.

Apheresis in low body weight children and adolescents is challenging due to a variety of technical and clinical issues including vascular access, low total blood volume, and hypotension. Although dogs have been a valuable preclinical model for apheresis, the procedure can be challenging since many pure-bred dogs are extremely small. Therefore, apheresis in these very small breeds presents very similar challenges as seen when performing the procedure in very low body weight people. We describe apheresis of four very small dogs, weighing from 4.6 to 7.6 kg, using either a COBESpectra and Spectra Optia apheresis system (Terumo BCT, Lakewood, CO, USA). Two dogs underwent large volume leukapheresis to collect mononuclear cells in preparation for hematopoietic stem cell transplantation and two dogs underwent therapeutic plasma exchange to treat an immune-mediated disease. In all cases, a dual-lumen hemodialysis catheter placed in the jugular vein provided adequate machine inlet and return flow rates. Machine priming was necessary to maintain hemodynamic stability during the beginning of the procedure, and rinseback was avoided for the same reason. Anticoagulant citrate dextrose solution, solution A was used for the large volume leukapheresis procedures and a combination of anticoagulant citrate dextrose solution, solution A and heparin was used for the therapeutic plasma exchange procedures. As such, serum iCa levels were regularly monitored and 10% calcium gluconate constant rate infusions were used to prevent citrate toxicity. All dogs completed the aphereses with no life-threatening adverse events. We conclude that aphereses in very small dogs is feasible if close attention is paid to hemodynamic stability and citrate toxicity.

Implementation of total body photon irradiation as part of an institutional bone marrow transplant program for the treatment of canine lymphoma and leukemias.

A total body irradiation (TBI) protocol was developed to support a bone marrow transplant (BMT) program for the treatment of canine hematologic malignancies. The purpose of this prospective study is to describe implementation of the protocol and resultant dosimetry. Nongraphic manual treatment planning using 6 MV photons, isocentric delivery, 40 × 40 cm field size, wall-mounted lasers to verify positioning, a lucite beam spoiler (without use of bolus material), a dose rate of 8.75 cGy/min at patient isocenter, and a source-to-axis distance of 338 cm were used for TBI. A monitor unit calculation formula was derived using ion chamber measurements and a solid water phantom. Five thermoluminescent dosimeters (TLDs) were used at various anatomic locations in each of four cadaver dogs, to verify fidelity of the monitor unit formula prior to clinical implementation. In vivo dosimetric data were then collected with five TLDs at various anatomic locations in six patients treated with TBI. A total dose of 10 Gy divided into two 5 Gy fractions was delivered approximately 16 h apart, immediately followed by autologous stem cell transplant. The mean difference between prescribed and delivered doses ranged from 99% to 109% for various sites in cadavers, and from 83% to 121% in clinical patients. The mean total body dose in cadavers and clinical patients when whole body dose was estimated by averaging doses measured by variably placed TLDs ranged from 98% to 108% and 93% to 102% of the prescribed dose, respectively, which was considered acceptable. This protocol could be used for institutional implementation of TBI.

Incidence and risk factors associated with development of clinical cardiotoxicity in dogs receiving doxorubicin.

BACKGROUND: Doxorubicin (DOX) can cause cumulative cardiotoxicity in dogs, but the incidence of clinical cardiotoxicity in dogs receiving DOX has not been determined. HYPOTHESIS/OBJECTIVES: To determine if the duration of DOX infusion influences the incidence of cardiotoxicity, to characterize the incidence of clinical cardiotoxicity in dogs during or after DOX chemotherapy, and to identify any risk factors associated with cardiotoxicity. ANIMALS: Four-hundred ninety-four dogs that received at least 1 dose of DOX for the treatment of cancer. METHODS: Retrospective study of dogs that received DOX from 2006 to 2015. RESULTS: Of 494 dogs, 20 (4.0%) developed clinical cardiotoxicity. The duration of DOX infusion was not significantly associated with clinical cardiotoxicity, whereas a higher cumulative dose of DOX, higher body weight, decreases in fractional shortening after 5 doses of DOX, and development of ventricular premature contractions were significantly associated with clinical cardiotoxicity. High-risk breeds for developing dilated cardiomyopathy had an incidence of 15.4%, whereas low-risk breeds had an incidence of 3.0%. CONCLUSIONS AND CLINICAL IMPORTANCE: Although the duration of DOX infusion did not influence the incidence of cardiotoxicity, premature contractions and decreases in fractional shortening should raise concern for the development of clinical cardiotoxicity. Overall, the incidence of clinical DOX-induced cardiotoxicity is low, but Boxers and other breeds at high risk for dilated cardiomyopathy may be at an increased risk.

The canine MHC class Ia allele DLA-88*508:01 presents diverse self- and canine distemper virus-origin peptides of varying length that have a conserved binding motif.

Ideally, CD8+ T-cell responses against virally infected or malignant cells are defined at the level of the specific peptide and restricting MHC class I element, a determination not yet made in the dog. To advance the discovery of canine CTL epitopes, we sought to determine whether a putative classical MHC class Ia gene, Dog Leukocyte Antigen (DLA)-88, presents peptides from a viral pathogen, canine distemper virus (CDV). To investigate this possibility, DLA-88*508:01, an allele prevalent in Golden Retrievers, was expressed as a FLAG-tagged construct in canine histiocytic cells to allow affinity purification of peptide-DLA-88 complexes and subsequent elution of bound peptides. Pattern analysis of self peptide sequences, which were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS), permitted binding preferences to be inferred. DLA-88*508:01 binds peptides that are 9-to-12 amino acids in length, with a modest preference for 9- and 11-mers. Hydrophobic residues are favored at positions 2 and 3, as are K, R or F residues at the C-terminus. Testing motif-matched and -unmatched synthetic peptides via peptide-MHC surface stabilization assay using a DLA-88*508:01-transfected, TAP-deficient RMA-S line supported these conclusions. With CDV infection, 22 viral peptides ranging from 9-to-12 residues in length were identified in DLA-88*508:01 eluates by LC-MS/MS. Combined motif analysis and surface stabilization assay data suggested that 11 of these 22 peptides, derived from CDV hemagglutinin, large polymerase, matrix, nucleocapsid, and V proteins, were processed and presented, and thus, potential targets of anti-viral CTL in DLA-88*508:01-bearing dogs. The presentation of diverse self and viral peptides indicates that DLA-88 is a classical MHC class Ia gene.

Comprehensive genomic characterization of five canine lymphoid tumor cell lines.

BACKGROUND: Leukemia/lymphoma cell lines have been critical in the investigation of the pathogenesis and therapy of hematological malignancies. While human LL cell lines have generally been found to recapitulate the primary tumors from which they were derived, appropriate characterization including cytogenetic and transcriptional assessment is crucial for assessing their clinical predictive value. RESULTS: In the following study, five canine LL cell lines, CLBL-1, Ema, TL-1 (Nody-1), UL-1, and 3132, were characterized using extensive immunophenotyping, karyotypic analysis, oligonucleotide array comparative genomic hybridization (oaCGH), and gene expression profiling. Genome-wide DNA copy number data from the cell lines were also directly compared with 299 primary canine round cell tumors to determine whether the cell lines represent primary tumors, and, if so, what subtype each most closely resembled. CONCLUSIONS: Based on integrated analyses, CLBL-1 was classified as B-cell lymphoma, Ema and TL-1 as T-cell lymphoma, and UL-1 as T-cell acute lymphoblastic leukemia. 3132, originally classified as a B-cell lymphoma, was reclassified as a histiocytic sarcoma based on characteristic cytogenomic properties. In combination, these data begin to elucidate the clinical predictive value of these cell lines which will enhance the appropriate selection of in vitro models for future studies of canine hematological malignancies.

Genome-wide assessment of recurrent genomic imbalances in canine leukemia identifies evolutionarily conserved regions for subtype differentiation.

Leukemia in dogs is a heterogeneous disease with survival ranging from days to years, depending on the subtype. Strides have been made in both human and canine leukemia to improve classification and understanding of pathogenesis through immunophenotyping, yet classification and choosing appropriate therapy remains challenging. In this study, we assessed 123 cases of canine leukemia (28 ALLs, 24 AMLs, 25 B-CLLs, and 46 T-CLLs) using high-resolution oligonucleotide array comparative genomic hybridization (oaCGH) to detect DNA copy number alterations (CNAs). For the first time, such data were used to identify recurrent CNAs and inclusive genes that may be potential drivers of subtype-specific pathogenesis. We performed predictive modeling to identify CNAs that could reliably differentiate acute subtypes (ALL vs. AML) and chronic subtypes (B-CLL vs. T-CLL) and used this model to differentiate cases with up to 83.3 and 95.8 % precision, respectively, based on CNAs at only one to three genomic regions. In addition, CGH datasets for canine and human leukemia were compared to reveal evolutionarily conserved copy number changes between species, including the shared gain of HSA 21q in ALL and ∼25 Mb of shared gain of HSA 12 and loss of HSA 13q14 in CLL. These findings support the use of canine leukemia as a relevant in vivo model for human leukemia and justify the need to further explore the conserved genomic regions of interest for their clinical impact.

Allogeneic hematopoietic cell transplantation in a dog with acute large granular lymphocytic leukemia.

CASE DESCRIPTION: A 3-year-old 10-kg (22-lb) neutered male Cavalier King Charles Spaniel was referred because of an episode of acute vomiting and diarrhea. CLINICAL FINDINGS: On physical examination, mild splenomegaly and prominent submandibular and popliteal lymph nodes were detected. Complete blood cell count revealed a high WBC count, characterized by a moderate lymphocytosis with 62% unclassified cells and severe thrombocytopenia with macroplatelets. On cytologic evaluation, the unclassified cells were described as large, neoplastic lymphoid cells containing a large nucleus with lacy chromatin and a large amount of blue vacuolated cytoplasm containing sparse, very fine azurophilic granules. A diagnosis of acute large granular lymphocytic leukemia of splenic origin was made. TREATMENT AND OUTCOME: Following induction chemotherapy, the affected dog underwent allogeneic hematopoietic cell transplantation with dog leukocyte antigen-matched CD34+ cells harvested from a sibling of the same litter. Chimerism analysis revealed full donor engraftment within 2 weeks after transplantation that remained stable for at least 2 years, with the dog remaining apparently healthy at home. CLINICAL RELEVANCE: Acute leukemias in dogs are rapidly fatal diseases. If an appropriate donor can be located, allogeneic hematopoietic cell transplantation may offer a feasible treatment, although peripheral blood CD34+ cell harvesting requires the availability of cell separator machines and management of graft-versus-host disease with immunosuppressive agents.

Man's best friend: what can pet dogs teach us about non-Hodgkin's lymphoma?

Animal models are essential for understanding lymphoma biology and testing new treatments prior to human studies. Spontaneously arising lymphomas in pet dogs represent an underutilized resource that could be used to complement current mouse lymphoma models, which do not adequately represent all aspects of the human disease. Canine lymphoma resembles human lymphoma in many important ways, including characteristic translocations and molecular abnormalities and similar therapeutic responses to chemotherapy, radiation, and newer targeted therapies (e.g. ibrutinib). Given the large number of pet dogs and high incidence of lymphoma, particularly in susceptible breeds, dogs represent a largely untapped resource for advancing the understanding and treatment of human lymphoma. This review highlights similarities in molecular biology, diagnosis, treatment, and outcomes between human and canine lymphoma. It also describes resources that are currently available to study canine lymphoma, advantages to be gained by exploiting the genetic breed structure in dogs, and current and future challenges and opportunities to take full advantage of this resource for lymphoma studies.

Evaluation of thromboelastography for prediction of clinical bleeding in thrombocytopenic dogs after total body irradiation and hematopoietic cell transplantation.

OBJECTIVE: To determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs following total body irradiation (TBI) and bone marrow transplantation (BMT). ANIMALS: 10 client-owned thrombocytopenic dogs with multicentric lymphoma. PROCEDURES: Results of a kaolin-activated thromboelastography assay, platelet count, and buccal mucosal bleeding time were evaluated for correlation to clinical bleeding. RESULTS: Maximum amplitude, derived via thromboelastography, was the only hemostatic variable with significant correlation to clinical bleeding. Buccal mucosal bleeding time had a high sensitivity but poor specificity for identifying dogs with clinical bleeding. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with buccal mucosal bleeding time and platelet count, thromboelastography was more reliable at identifying thrombocytopenic dogs with a low risk of bleeding and could be considered to help guide the use of transfusion products in dogs undergoing TBI and BMT.

VH1-44 gene usage defines a subset of canine B-cell lymphomas associated with better patient survival.

The use of specific immunoglobulin heavy chain variable region (VH) genes has been associated with increased patient survival in human B-cell lymphomas (hBCL). Given the similarity of human and canine BCL (cBCL) in morphology and clinical treatment, we examined the choice of VH in cBCL and determined whether VH gene selection was a distinct feature associated with survival time in dogs. VH gene selection and mutational status in 52 cBCL, including 29 diffuse large B-cell lymphomas (cDLBCL, the most common subtype of cBCL), were analyzed by comparison with the 80 published canine germline VH gene sequences. We further examined the prognostic impact of the subgroups defined by these features on canine survival. We found that VH1-44 was preferentially expressed in the majority of the 52 cBCLs (60%) as well as in the majority of the cDLBCL subset (59%). VH1-44 gene expression was associated with a statistically better overall survival (p=0.039) in cBCL patients, as well as in the cDLBCL subset of patients (p=0.038). These findings suggest that VH gene selection in cBCL is not random and may therefore have functional implications for cBCL lymphomagenesis, in addition to being a useful prognostic biomarker.

Expression of asparagine synthetase predicts in vitro response to L-asparaginase in canine lymphoid cell lines.

l-asparaginase (L-asp), a bacterial enzyme that depletes extracellular asparagine, is used to treat acute lymphoblastic leukemia in humans and a variety of aggressive lymphoid malignancies in dogs. Resistance to this drug is an important cause of treatment failure in both species. Using canine lymphoid cell lines, we found that L-asp sensitivity is strongly negatively correlated with the level of methylation of the asparagine synthetase (ASNS) promoter. Selection for in vitro resistance was accompanied by increased ASNS promoter methylation and decreased ASNS mRNA expression. In addition, treatment with the hypomethylating agent 5-azacytidine increased resistance to L-asp. ASNS methylation and expression is not predictive of overall survival or progression-free survival in canine lymphoma patients treated with L-asp. Our data suggest that ASNS is an important factor in mediating the in vitro response of canine lymphoid cells to L-asp; however, resistance mechanisms may be more complex in dogs treated clinically with L-asp, potentially due to concurrent treatments.

Gene profiling of canine B-cell lymphoma reveals germinal center and postgerminal center subtypes with different survival times, modeling human DLBCL.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, and fewer than half of patients are cured with standard first-line therapy. To improve therapeutic options, better animal models that accurately mimic human DLBCL (hDLBCL) are needed. Canine DLBCL, one of the most common cancers in veterinary oncology, is morphologically similar to hDLBCL and is treated using similar chemotherapeutic protocols. With genomic technologies, it is now possible to molecularly evaluate dogs as a potential large-animal model for hDLBCL. We evaluated canine B-cell lymphomas (cBCL) using immunohistochemistry (IHC) and gene expression profiling. cBCL expression profiles were similar in many ways to hDLBCLs. For instance, a subset had increased expression of NF-κB pathway genes, mirroring human activated B-cell (ABC)-type DLBCL. Furthermore, immunoglobulin heavy chain ongoing mutation status, which is correlated with ABC/germinal center B-cell cell of origin in hDLBCL, separated cBCL into two groups with statistically different progression-free and overall survival times. In contrast with hDLBCL, cBCL rarely expressed BCL6 and MUM1/IRF4 by IHC. Collectively, these studies identify molecular similarities to hDLBCL that introduce pet dogs as a representative model of hDLBCL for future studies, including therapeutic clinical trials.

Apheresis in three dogs weighing <14 kg.

HISTORY: CaridianBCT apheresis machines require a ~285 mL priming volume (extracorporeal blood) that is withdrawn from the patient in ~10 minutes. Therefore, apheresis in dogs has generally been limited to dogs > ~20 kg to assure <20% of the blood volume is removed in the priming phase. ANIMALS/PHYSICAL EXAMINATION: Three dogs weighing <14 kg (13.6, 10.5, and 9.9 kg) with lymphoma that underwent apheresis. MANAGEMENT: The dogs were premedicated for placement of apheresis catheters with hydromorphone (0.1 mg kg(-1) ) IM. Anesthesia was induced with propofol, to effect, intravenously and general anesthesia was maintained with isoflurane in oxygen. Following catheter placement, dogs were allowed to recover from isoflurane but were kept sedated with either a dexmedetomidine constant rate infusion (CRI) or a propofol CRI. Real time autologous blood priming was not performed in any of the dogs. Instead, priming solutions were composed of a combination of hetastarch, lactated Ringer's solution, and/or autologous blood that was harvested 4 days before the procedure. During apheresis, dogs received anticoagulant citrate-dextrose, solution-A (ACD-A) to prevent clotting and 10% calcium gluconate as needed to maintain normal ionized calcium concentrations. Dogs were monitored for cardiovascular and cardiopulmonary stability, anemia and lactic acidosis. FOLLOW-UP: All of the dogs had cardiovascular and cardiopulmonary values within clinically acceptable ranges. Immediately following apheresis all of the dogs were mildly to moderately anemic (PCV; 17-35%) although none of the dogs required a transfusion or had an increased lactate concentration. CONCLUSIONS: Dogs as small as 9.9 kg can successfully undergo apheresis with a variety of priming solutions. Dexmedetomidine or propofol given as a CRI provides sufficient sedation for this procedure.