Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus.

Aim: To molecularly characterize the tumor microenvironment and evaluate immunologic parameters in canine glioma patients before and after treatment with oncolytic human IL-12-expressing herpes simplex virus (M032) and in treatment naïve canine gliomas. Methods: We assessed pet dogs with sporadically occurring gliomas enrolled in Stage 1 of a veterinary clinical trial that was designed to establish the safety of intratumoral oncoviral therapy with M032, a genetically modified oncolytic herpes simplex virus. Specimens from dogs in the trial and dogs not enrolled in the trial were evaluated with immunohistochemistry, NanoString, Luminex cytokine profiling, and multi-parameter flow cytometry. Results: Treatment-naive canine glioma microenvironment had enrichment of Iba1 positive macrophages and minimal numbers of T and B cells, consistent with previous studies identifying these tumors as immunologically "cold". NanoString mRNA profiling revealed enrichment for tumor intrinsic pathways consistent with suppression of tumor-specific immunity and support of tumor progression. Oncolytic viral treatment induced an intratumoral mRNA transcription signature of tumor-specific immune responses in 83% (5/6) of canine glioma patients. Changes included mRNA signatures corresponding with interferon signaling, lymphoid and myeloid cell activation, recruitment, and T and B cell immunity. Multiplexed protein analysis identified a subset of oligodendroglioma subjects with increased concentrations of IL-2, IL-7, IL-6, IL-10, IL-15, TNFα, GM-CSF between 14 and 28 days after treatment, with evidence of CD4+ T cell activation and modulation of IL-4 and IFNγ production in CD4+ and CD8+ T cells isolated from peripheral blood. Conclusion: These findings indicate that M032 modulates the tumor-immune microenvironment in the canine glioma model.

Canine NAPEPLD-associated models of human myelin disorders.

Canine leukoencephalomyelopathy (LEMP) is a juvenile-onset neurodegenerative disorder of the CNS white matter currently described in Rottweiler and Leonberger dogs. Genome-wide association study (GWAS) allowed us to map LEMP in a Leonberger cohort to dog chromosome 18. Subsequent whole genome re-sequencing of a Leonberger case enabled the identification of a single private homozygous non-synonymous missense variant located in the highly conserved metallo-beta-lactamase domain of the N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD) gene, encoding an enzyme of the endocannabinoid system. We then sequenced this gene in LEMP-affected Rottweilers and identified a different frameshift variant, which is predicted to replace the C-terminal metallo-beta-lactamase domain of the wild type protein. Haplotype analysis of SNP array genotypes revealed that the frameshift variant was present in diverse haplotypes in Rottweilers, and also in Great Danes, indicating an old origin of this second NAPEPLD variant. The identification of different NAPEPLD variants in dog breeds affected by leukoencephalopathies with heterogeneous pathological features, implicates the NAPEPLD enzyme as important in myelin homeostasis, and suggests a novel candidate gene for myelination disorders in people.

Effect of Cranberry Extract on the Frequency of Bacteriuria in Dogs with Acute Thoracolumbar Disk Herniation: A Randomized Controlled Clinical Trial.

BACKGROUND: Dogs with spinal cord injury are at increased risk of developing bacteriuria due to increased residual urine volume. Cranberry extract inhibits binding of E. coli to uroepithelial cells, potentially reducing risk of bacteriuria. HYPOTHESIS: Cranberry extract reduces risk of bacteriuria in dogs after acute TL-IVDH. ANIMALS: Client-owned dogs with acute onset TL-IVDH causing nonambulatory status. METHODS: Randomized, placebo-controlled, blinded, prospective clinical trial. Dogs with acute TL-IVDH were recruited 48 hours postoperatively and randomized to receive cranberry extract or placebo in a masked fashion. Urine cultures and neurological examinations were performed 2, 4, and 6 weeks postoperatively. The number of dogs with bacteriuria (all bacterial species) and bacteriuria (E. coli) were primary and secondary outcome measures and were evaluated using chi-squared test. Urine antiadhesion activity (AAA) was measured in a subset (N = 47) and examined in a secondary analysis evaluating additional risk factors for bacteriuria. RESULTS: Bacteriuria was detected 17 times in 94 dogs (6 placebo, 11 cranberry, P = .12). There were 7 E. coli. positive cultures (1 placebo, 6 cranberry, P = .09). Dogs in both groups had positive urine AAA (14/21: placebo, 16/26: cranberry), and dogs with urine AAA had significantly fewer E. coli positive cultures (n = 1) than dogs without it (n = 4) (P = .047). CONCLUSIONS AND CLINICAL IMPORTANCE: This clinical trial did not show a benefit of oral cranberry extract but had low power. Cranberry extract supplementation did not impact urine AAA, but a possible association between urine AAA and lower risk of E. coli bacteriuria was identified. Other doses could be investigated.

Hydrocephalus secondary to obstruction of the lateral apertures in two dogs.

BACKGROUND: Traditionally, hydrocephalus is divided into communicating or non-communicating (obstructive) based on the identification of a blockage of cerebrospinal fluid (CSF) flow through the ventricular system. Hydrocephalus ex vacuo refers to ventricular enlargement as a consequence of neuroparenchymal loss. Hydrocephalus related to obstruction of the lateral apertures of the fourth ventricles has rarely been described. CASE REPORT: The clinicopathologic findings in two dogs with hydrocephalus secondary to obstruction of the lateral apertures of the fourth ventricle are reported. Signs were associated with a caudal cervical spinal cord lesion in one dog and a caudal brain stem lesion in the other dog. Magnetic resonance imaging (MRI) disclosed dilation of the ventricular system, including the lateral recesses of the fourth ventricle. In one dog, postmortem ventriculography confirmed obstruction of the lateral apertures. Microscopic changes were identified in the choroid plexus in both dogs, yet a definitive cause of the obstructions was not identified. The MRI findings in both dogs are similar to membranous occlusion of the lateral and median apertures in human patients. CONCLUSION: MRI detection of dilation of the entire ventricular system in the absence of an identifiable cause should prompt consideration of an obstruction of the lateral apertures. In future cases, therapeutic interventions aimed at re-establishing CSF flow or ventriculoperitoneal catheterisation should be considered.

2015 ACVIM Small Animal Consensus Statement on Seizure Management in Dogs.

This report represents a scientific and working clinical consensus statement on seizure management in dogs based on current literature and clinical expertise. The goal was to establish guidelines for a predetermined, concise, and logical sequential approach to chronic seizure management starting with seizure identification and diagnosis (not included in this report), reviewing decision-making, treatment strategies, focusing on issues related to chronic antiepileptic drug treatment response and monitoring, and guidelines to enhance patient response and quality of life. Ultimately, we hope to provide a foundation for ongoing and future clinical epilepsy research in veterinary medicine.

A Placebo-Controlled, Prospective, Randomized Clinical Trial of Polyethylene Glycol and Methylprednisolone Sodium Succinate in Dogs with Intervertebral Disk Herniation.

BACKGROUND: Acute intervertebral disk herniation (IVDH) is a common cause of spinal cord injury in dogs and currently there is no proven medical treatment to counter secondary injury effects. Use of methylprednisolone sodium succinate (MPSS) or polyethylene glycol (PEG) as neuroprotectants is advocated but controversial because neither treatment has been tested in placebo-controlled, randomized, blinded trials in dogs. HYPOTHESIS: Polyethylene glycol will improve the outcome of severe spinal cord injury caused by IVDH compared to MPSS or placebo. ANIMALS: Client-owned dogs with acute onset of thoracolumbar IVDH causing paralysis and loss of nociception for <24 hours. METHODS: Dogs were randomized to receive MPSS, PEG, or placebo; drugs appeared identical and group allocation was masked. Drug administration was initiated once the diagnosis of IVDH was confirmed and all dogs underwent hemilaminectomy. Neurologic function was assessed 2, 4, 8, and 12 weeks postoperatively using an open field gait score (OFS) as the primary outcome measure. Outcomes were compared by the Wilcoxon rank sum test. RESULTS: Sixty-three dogs were recruited and 47.6% recovered ambulation. 17.5% developed progressive myelomalacia but there was no association with group. There was no difference in OFS among groups. Although full study power was not reached, conditional power analyses indicated the futility of continued case recruitment. CONCLUSIONS: This clinical trial did not show a benefit of either MPSS or PEG in the treatment of acute, severe thoracolumbar IVDH when used as adjunctive medical treatment administered to dogs presenting within 24 hours of onset of paralysis.

An additional middle cuneiform?

Additional cuneiform bones of the foot have been described in reference to the medial bipartite cuneiform or as small accessory ossicles. An additional middle cuneiform has not been previously documented. We present the case of a patient with an additional ossicle that has the appearance and location of an additional middle cuneiform. Recognizing such an anatomical anomaly is essential for ruling out second metatarsal base or middle cuneiform fractures and for the preoperative planning of arthrodesis or open reduction and internal fixation procedures in this anatomical location.

Chiari-like malformation and syringomyelia in American Brussels Griffon dogs.

BACKGROUND: Although Chiari-like malformation (CM) and syringomyelia (SM) have been described in many small breed dogs, the prevalence and clinical manifestations of this complex have not been documented in a large cohort of American Brussels Griffon (ABG) dogs. OBJECTIVES: To characterize the clinical and magnetic resonance imaging (MRI) features of CM and SM in the ABG breed. ANIMALS: Eighty-four American Kennel Club registered ABG dogs were recruited. METHODS: Prospective study. Complete histories and neurologic examinations were obtained before MRI. Images were blindly reviewed and calculations were made by using OsiriX. All analyses were performed by Student's t-test, Spearman's correlation, ANOVA, and chi-square test where appropriate. RESULTS: Chiari-like malformation and SM were present in 65% and 52% of dogs, respectively. Twenty-eight percent of dogs had neurologic deficits and 20% had neck pain. Mean central canal (CC) transverse height was 2.5 mm with a mean length of 3.6 cervical vertebrae. Neurologic deficits were significantly associated with a larger syrinx (P = .04, P = .08) and syrinx size increased with age (P = .027). SM was associated with a smaller craniocervical junction (CCJ) height (P = .04) and larger ventricles (P = .0001; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Syringomyelia and CM are prevalent in American Brussels Griffon dogs. Syrinx size is associated with neurologic deficits, CM, larger ventricles, a smaller craniocervical junction height, neurologic deficits, and cerebellar herniation. Fifty-two percent of dogs with a SM were clinically normal.

Prognostic value of early magnetic resonance imaging in dogs after traumatic brain injury: 50 cases.

BACKGROUND: The prognostic value of early magnetic resonance imaging (MRI) in dogs after traumatic brain injury (TBI) remains unclear. OBJECTIVES: Determine whether MRI findings are associated with prognosis after TBI in dogs. ANIMALS: Fifty client-owned dogs. METHODS: Retrospective study of dogs with TBI that underwent 1.5T MRI within 14 days after head trauma. MRI evaluators were blinded to the clinical presentation, and all images were scored based on an MRI grading system (Grade I [normal brain parenchyma] to Grade VI [bilateral lesions affecting the brainstem with or without any lesions of lesser grade]). Skull fractures, percentage of intraparenchymal lesions, degree of midline shift, and type of brain herniation were evaluated. MGCS was assessed at presentation. The presence of seizures was recorded. Outcome was assessed at 48 h (alive or dead) and at 3, 6, 12, and 24 months after TBI. RESULTS: Sixty-six percent of the dogs had abnormal MRI findings. MRI grade was negatively correlated (P < .001) with MGCS. A significant negative correlation of MRI grade, degree of midline shift, and percentage of intraparenchymal lesions with follow-up scores was identified. The MGCS was lower in dogs with brain herniation (P = .0191). Follow-up scores were significantly lower in dogs that had brain herniation or skull fractures. The possibility of having seizures was associated with higher percentage of intraparenchymal lesions (P = 0.0054) and 10% developed PTE. CONCLUSIONS AND CLINICAL IMPORTANCE: Significant associations exist between MRI findings and prognosis in dogs with TBI. MRI can help to predict prognosis in dogs with TBI.

Prevalence of effusion in the tympanic cavity in dogs with dysfunction of the trigeminal nerve: 18 cases (2004-2013).

BACKGROUND: Animals with disorders involving the trigeminal nerve or its nuclei in the brainstem can have effusion in the tympanic cavity ipsilateral to the side of the neurological deficits. The tensor veli palatini muscle (TVP), innervated by the mandibular branch of the trigeminal nerve, opens the pharyngeal orifice of the auditory tube. With denervation of the TVP, dysfunction of the auditory tube may occur, which could lead to effusion. HYPOTHESIS/OBJECTIVES: To determine the prevalence of effusion in the tympanic cavity in dogs with disorders involving the trigeminal nerve. ANIMALS: Eighteen client-owned dogs were evaluated retrospectively. METHODS: Retrospective study. RESULTS: Diagnostic imaging databases were searched for dogs having undergone magnetic resonance imaging (MRI) evaluation for signs referable to dysfunction of the trigeminal nerve. Signalment and neurological examination findings were recorded. The MRI study was evaluated for the presence or absence of effusion. MRI characteristics of the affected trigeminal nerve and the muscles of mastication were recorded. Based on the location of the trigeminal nerve lesion, dogs were divided into three categories: brainstem, trigeminal canal, or extracranial. Eighteen dogs met the inclusion criteria. Six of 18 dogs (33%) had effusion in the tympanic cavity ipsilateral to the affected trigeminal nerve. CONCLUSION AND CLINICAL IMPORTANCE: A substantial proportion of dogs with a lesion affecting the trigeminal nerve had effusion in the tympanic cavity. This finding likely represents denervation of the TVP muscle, which may have led to dysfunction of the auditory tube.

Canine idiopathic epilepsy: prevalence, risk factors and outcome associated with cluster seizures and status epilepticus.

OBJECTIVES: To evaluate the prevalence of cluster seizures and status epilepticus in dogs with idiopathic epilepsy and determine risk factors for cluster seizure frequency, severity and patient outcome. METHODS: Retrospective review of medical records of 407 dogs with idiopathic epilepsy was made. Follow-up questionnaires were evaluated in cases with cluster seizures. RESULTS: Mean age at diagnosis of idiopathic epilepsy was 4 years. Cluster seizures were documented in 169 (41%) dogs. German shepherds and boxers were significantly (P=0·04 and 0·01, respectively) more likely to suffer from cluster seizures compared to Labrador retrievers. There was no association between the occurrence of status epilepticus and cluster seizures and frequency and severity of cluster seizures and status epilepticus episodes with age or breed. Intact males were twice as likely (P=0·003) than neutered dogs to suffer from cluster seizures. Intact females had significantly (P=0·007) more frequent cluster seizures than neutered dogs. The median survival time for all dogs with cluster seizures was 95 months. Significantly (P=0·03) more dogs with frequent cluster seizures were euthanased because of the cluster seizures. CLINICAL SIGNIFICANCE: There was a high prevalence of cluster seizures in dogs with idiopathic epilepsy. Neutering status appears to influence cluster seizure occurrence with intact females more likely to experience more frequent episodes. Euthanasia is associated with frequency of cluster seizure episodes.

Magnetic resonance imaging for the differentiation of neoplastic, inflammatory, and cerebrovascular brain disease in dogs.

BACKGROUND: The reliability and validity of magnetic resonance imaging (MRI) for detecting neoplastic, inflammatory, and cerebrovascular brain lesions in dogs are unknown. OBJECTIVES: To estimate sensitivity, specificity, and inter-rater agreement of MRI for classifying histologically confirmed neoplastic, inflammatory, and cerebrovascular brain disease in dogs. ANIMALS: One hundred and twenty-one client-owned dogs diagnosed with brain disease (n = 77) or idiopathic epilepsy (n = 44). METHODS: Retrospective, multi-institutional case series; 3 investigators analyzed MR images for the presence of a brain lesion with and without knowledge of case clinical data. Investigators recorded most likely etiologic category (neoplastic, inflammatory, cerebrovascular) and most likely specific disease for all brain lesions. Sensitivity, specificity, and inter-rater agreement were calculated to estimate diagnostic performance. RESULTS: MRI was 94.4% sensitive (95% confidence interval [CI] = 88.7, 97.4) and 95.5% specific (95% CI = 89.9, 98.1) for detecting a brain lesion with similarly high performance for classifying neoplastic and inflammatory disease, but was only 38.9% sensitive for classifying cerebrovascular disease (95% CI = 16.1, 67.0). In general, high specificity but not sensitivity was retained for MR diagnosis of specific brain diseases. Inter-rater agreement was very good for overall detection of structural brain lesions (κ = 0.895, 95% CI = 0.792, 0.998, P < .001) and neoplastic lesions, but was only fair for cerebrovascular lesions (κ = 0.299, 95% CI = 0, 0.761, P = .21). CONCLUSIONS AND CLINICAL IMPORTANCE: MRI is sensitive and specific for identifying brain lesions and classifying disease as inflammatory or neoplastic in dogs. Cerebrovascular disease in general and specific inflammatory, neoplastic, and cerebrovascular brain diseases were frequently misclassified.

Magnetic resonance imaging enhancement of intervertebral disc disease in 30 dogs following chemical fat saturation.

OBJECTIVE: To describe the patterns of enhancement of extradural intervertebral disc on chemically fat saturated gadolinium-enhanced magnetic resonance images and to investigate the clinical and pathological associations with enhancement. METHODS: Medical records and magnetic resonance images were reviewed from 30 dogs with histopathologically confirmed disc disease and enhancement on a T1-weighted postcontrast fat saturated sequence. RESULTS: Median duration of neurological signs was 4 days and the most common grade of severity was II, seen in 46·6% of dogs. Homogeneous, heterogeneous and peripheral patterns of disc enhancement were described, with peripheral enhancement most commonly identified (57% of dogs). There were no clinical or pathological differences between the dogs with each of the patterns. The mean signal intensity of a region of interest within the extruded disc material and contrast-to-noise ratio of the disc material were significantly higher on postcontrast T1-weighted fat saturated images (P=<0·0001 each). CLINICAL SIGNIFICANCE: The use of fat saturated gadolinium-enhanced magnetic resonance imaging can detect enhancement of extradural disc material. Patterns of enhancement are not associated with the clinical presentation or pathological features.