RESOLUTION OF CALVARIAL HYPEROSTOSIS IN AFRICAN LION CUBS (PANTHERA LEO LEO) AFTER VITAMIN A SUPPLEMENTATION.

Two female (FL 1, FL 2) and one male (ML) 11-wk-old, intact, captive African lion cubs (Panthera leo leo) were presented with a history of mild vestibular signs. Initial serum vitamin A concentrations were low (140 nmol/L) for ML. Calvarial hyperostosis was confirmed using computed tomography (CT) of the head and cervical vertebrae in each cub. CT measurements were adapted in relation to the skull width. ML showed the most pronounced thickening of the tentorium cerebelli and occipital bone, represented by a tentorium cerebelli to skull width ratio (TCR) of 0.08 (FL 1: 0.06, FL 2: 0.05) and a basisphenoid to skull width ratio (BBR) of 0.07 (FL 1: 0.06, FL 2: 0.04). Magnetic resonance imaging (MRI) revealed cerebellar herniation and cervical intramedullary T2-weighted hyperintensity from C1, extending caudally for at least two cervical vertebrae in all cubs. Treatment was initiated with subcutaneous vitamin A supplementation and feeding of whole carcasses. Improvement in ataxia was noticed 3 wk later. Follow-up CT and MRI examinations were performed in ML after 3 and 8 mon. The affected bones appeared slightly less thickened and TCR and BBR had decreased to 0.05 after 3 mon. The cerebellum remained mildly herniated, accompanied by amelioration of cervical T2w hyperintensities. After 8 mon, evaluation and diagnostic imaging revealed further improvement regarding the neurologic status and measurements (TCR 0.05, BBR 0.04) despite persistence of a subtle cerebellar herniation. In conclusion, bone remodeling and improvement in clinical signs may be achievable in young lion cubs presented with calvarial hyperostosis and may be attributable to high-dose vitamin A supplementation.

The role of neuroinflammation in canine epilepsy.

The lack of therapeutics that prevent the development of epilepsy, improve disease prognosis or overcome drug resistance represents an unmet clinical need in veterinary as well as in human medicine. Over the past decade, experimental studies and studies in human epilepsy patients have demonstrated that neuroinflammatory processes are involved in epilepsy development and play a key role in neuronal hyperexcitability that underlies seizure generation. Targeting neuroinflammatory signaling pathways may provide a basis for clinically relevant disease-modification strategies in general, and moreover, could open up new therapeutic avenues for human and veterinary patients with drug-resistant epilepsy. A sound understanding of the neuroinflammatory mechanisms underlying seizure pathogenesis in canine patients is therefore essential for mechanism-based discovery of selective epilepsy therapies that may enable the development of new disease-modifying treatments. In particular, subgroups of canine patients in urgent needs, e.g. dogs with drug-resistant epilepsy, might benefit from more intensive research in this area. Moreover, canine epilepsy shares remarkable similarities in etiology, disease manifestation, and disease progression with human epilepsy. Thus, canine epilepsy is discussed as a translational model for the human disease and epileptic dogs could provide a complementary species for the evaluation of antiepileptic and antiseizure drugs. This review reports key preclinical and clinical findings from experimental research and human medicine supporting the role of neuroinflammation in the pathogenesis of epilepsy. Moreover, the article provides an overview of the current state of knowledge regarding neuroinflammatory processes in canine epilepsy emphasizing the urgent need for further research in this specific field. It also highlights possible functional impact, translational potential and future perspectives of targeting specific inflammatory pathways as disease-modifying and multi-target treatment options for canine epilepsy.

Assessment of oligoclonal bands in cerebrospinal fluid and serum of dogs with meningoencephalitis of unknown origin.

BACKGROUND: Meningoencephalitis of unknown origin (MUO) is an inflammatory disease of the canine central nervous system (CNS) that shares several features with multiple sclerosis (MS) in humans. In approximately 95% of MS patients, ≥ two immunoglobulin G (IgG) oligoclonal bands (OCBs) are detectable exclusively in the cerebrospinal fluid (CSF). HYPOTHESIS/OBJECTIVES: To investigate OCBs in CSF and serum in dogs affected by MUO, intervertebral disc disease (IVDD), idiopathic epilepsy (IE), intracranial neoplasia (IN), steroid-responsive meningitis-arteritis (SRMA), and diseases outside the CNS. We hypothesize that the highest prevalence of CSF-specific OCBs (≥ two OCBs uniquely in the CSF) would be found in dogs affected by MUO. ANIMALS: Client-owned dogs (n = 121) presented to the neurology service due to neurological deficits. METHODS: Prospective study. Measurement of IgG concentration in CSF and serum via a canine IgG ELISA kit. OCB detection via isoelectric focusing (IEF) and immunoblot. RESULTS: Presence of CSF-specific OCBs was significantly higher in dogs with MUO (57%) compared to 22% in IN, 6% in IE, 15% in SRMA, 13% in IVDD, and 0% in the non-CNS group (p < .001). Dogs with MUO were 9.9 times more likely to show CSF-specific OCBs than all other diseases together (95% confidence interval, 3.7-26.4; p < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: MUO showed the highest prevalence of CSF-specific OCBs, indicating an inflammatory B cell response. Future studies are needed to evaluate the prevalence in the specific MUO subtypes and a possible similarity with human MS.

Perception of challenges in management of neurological cases in the emergency room.

OBJECTIVE: To investigate emergency clinicians' comfort level in assessing neurological emergencies and to identify opportunities to foster enhanced training of clinical neurology in the emergency room. DESIGN: Internet-based survey. SETTING: University teaching hospitals and private referral centers. SUBJECTS: One hundred and ninety-two emergency and critical care specialists and resident trainees (ECC) and 104 neurology specialists and resident trainees (NEUR) in clinical practice. INTERVENTIONS: An internet-based survey was distributed via veterinary professional organizations' listserves and message boards and responses were collected between March and April 2020. ECC completed a survey evaluating stress levels associated with neurological emergencies, confidence with neurological examinations, and neuroanatomical localization. NEUR completed a similar survey to report their perception of their ECC colleagues' confidence in the assessment of neurological cases. Chi-square and Mann-Whitney U-tests were used to compare categorical responses and confidence scores between groups. P < 0.002 was considered significant. MEASUREMENTS AND MAIN RESULTS: Fifty-two percent of ECC found neurological emergencies slightly challenging, whereas 85% of NEUR found them moderately to extremely challenging for ECC (P < 0.0001). ECC's median self-reported confidence score in performing a neurologic examination on a scale of 0-100 was 75 (interquartile range [IQR], 27), while NEUR reported a median ECC confidence of 44 (IQR, 25; P < 0.0001). Median self-reported ECC confidence in localizing intracranial, spinal, and neuromuscular disease was 67 (IQR, 40), 88 (IQR, 21), and 60 (IQR, 37), respectively, which was significantly higher than median NEUR-reported ECC confidence of 35 (IQR, 38), 51 (IQR, 31), and 18 (IQR, 20), respectively (all P < 0.0001). Following case transfer, 34% of ECC received NEUR feedback in >75% of cases. CONCLUSIONS: Noticeable discrepancies between ECC and NEUR perceptions of ECC clinical confidence were seen, while no firm evidence of neurophobia could be inferred. Improvements in interdepartmental communication and teaching of clinical neurology may be warranted.

Otitis media and interna with or without polyps in cats: association between meningeal enhancement on postcontrast MRI, cerebrospinal fluid abnormalities, and clinician treatment choice and outcome.

OBJECTIVES: The aim of this study was to evaluate the association between meningeal enhancement (MgE) and cerebrospinal fluid (CSF) analysis results, their individual association with bacteriology results from affected ear samples and whether these test results influenced clinicians' therapeutic choice in cats with otitis media and interna (OMI). METHODS: This was a multicentre retrospective study carried out over an 8-year period. Cats diagnosed with OMI, with or without a nasopharyngeal polyp, leading to peripheral vestibular signs were included. Only cats for which MRI with postcontrast T1-weighted sequences and CSF analyses available were included. Cats with intra-axial MRI lesions or empyema were excluded. RESULTS: Fifty-eight cats met the inclusion criteria. MgE was reported in 26/58 cases, of which nine had an abnormal CSF result (increased total nucleated cell count [TNCC] or total protein); 32/58 cases had no MgE, of which 10 showed abnormal CSF results. There was no association between bacteriology results (external ear canal or bulla) and MgE or abnormal CSF results. CSF abnormalities were statistically significantly more common in acute cases (n = 16/37) than in chronic cases (n = 3/21; Fischer's test P = 0.04). Prednisolone was prescribed in 10/16 cases with increased TNCC. Among the 42 cases with normal TNCC, 15 received prednisolone and 13 received non-steroidal anti-inflammatory drugs. Various antimicrobial drugs were prescribed in 53/58 cats. Duration of antimicrobial treatment was similar, regardless of positive bacterial culture (5.58 vs 4.22 weeks), abnormal CSF (5.83 vs 4.76 weeks) or MgE (5.33 vs 4.90 weeks). CONCLUSIONS AND RELEVANCE: No association was found between the CSF and MgE results. Furthermore, no association was found between MgE, CSF or bacteriology findings. In addition, abnormal CSF results might lead the clinician to treat with corticosteroids, but they did not have any impact on duration of antimicrobial treatment. CSF abnormalities were seen significantly less frequently in chronic cases. The outcome tended to be poorer when MgE was detected on MRI.

Comparison of Two Different Canine Anti-IgG Antibodies for Assessment of Oligoclonal Bands in Cerebrospinal Fluid and Serum of Dogs via Isoelectric Focusing Followed by an Immunoblot.

Isoelectric focusing followed by immunoblotting is a method routinely used in human medicine to assess the presence of oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) and serum. The detection of OCBs is a valuable diagnostic test, especially important in patients with the suspicion of multiple sclerosis (MS), in which at least two OCBs are found in the CSF not present in paired serum samples in up to 95% of patients. So far, presence of OCBs in CSF and serum of dogs has only been investigated in a small cohort of dogs diagnosed with degenerative myelopathy and healthy dogs. The main objective of the current study was to describe the method used for OCB detection and compare two different canine anti-IgG antibodies: a canine rabbit-anti-IgG antibody (Jackson ImmunoResearch) vs. a canine goat-anti-IgG antibody (Bio-Rad). The method was performed according to the instructions of the commercial kit used. The canine goat-anti-IgG antibody showed a better performance than the canine rabbit-anti-IgG antibody. The availability of the technique of OCB detection in the dog paves the way for further studies, especially in the field of inflammatory diseases of the canine central nervous system, and comparison between specific human and canine diseases.

Neuronal current imaging: An experimental method to investigate electrical currents in dogs with idiopathic epilepsy.

BACKGROUND: The diagnosis of idiopathic epilepsy (IE) in dogs is based on exclusion of other potential causes of seizures. Recently, a novel magnetic resonance imaging (MRI) sequence that utilizes a variant of the rotary saturation approach has been suggested to detect weak transient magnetic field oscillations generated by neuronal currents in humans with epilepsy. HYPOTHESIS/OBJECTIVES: Effects on the magnetic field evoked by intrinsic epileptic activity can be detected by MRI in the canine brain. As proof-of-concept, the novel MRI sequence to detect neuronal currents was applied in dogs. ANIMALS: Twelve dogs with IE and 5 control dogs without a history of epileptic seizures were examined. METHODS: Prospective case-control study as proof-of-concept. All dogs underwent a clinical neurological examination, scalp electroencephalography, cerebrospinal fluid analysis, and MRI. The MRI examination included a spin-locking (SL) experiment applying a low-power on-resonance radiofrequency pulse in a predefined frequency domain in the range of oscillations generated by the epileptogenic tissue. RESULTS: In 11 of 12 dogs with IE, rotary saturation effects were detected by the MRI sequence. Four of 5 control dogs did not show rotary saturation effects. One control dog with a diagnosis of neuronal ceroid lipofuscinosis had SL-related effects, but did not have epileptic seizures clinically. CONCLUSIONS AND CLINICAL IMPORTANCE: The proposed MRI method detected neuronal currents in dogs with epileptic seizures and represents a potential new line of research to investigate neuronal currents possibly related to IE in dogs.

Accuracy and Safety of Image-Guided Freehand Pin Placement in Canine Cadaveric Vertebrae.

OBJECTIVE: The aim of this study was to validate an imaging technique for evaluation of spinal surgery accuracy and to establish accuracy and safety of freehand technique in the thoracolumbar spine of large breed dogs. STUDY DESIGN: After thoracolumbar spine computed tomography (CT), 26 drilling corridors were planned then drilled to receive 3.2 mm positive profile pins using a freehand technique. After pin removal, CT was repeated. All entry points, exit points and angles of the preoperative planned trajectories were compared with postoperative ones using an image registration and fusion technique by three observers. Corridor coordinates for entry and exit points were evaluated in three dimensions and angles were measured in one plane. Intraclass correlation coefficient (ICC) was used to establish the imaging technique reliability and descriptive statistics were used to report on the freehand technique accuracy. Safety was evaluated using a vertebral cortical breach grading scheme. RESULTS: Intraclass correlation coefficient for the entry points, exit points and angle were 0.79, 0.96 and 0.92 respectively. Mean deviations for the entry points, exit points and angle were 3.1 mm, 6.3 mm and 7.6 degrees respectively. Maximum deviations were 6.3 mm, 11.0 mm and 16.4 degrees. Most deviations were lateral and caudal. All corridors were judged as safe. CONCLUSION: The imaging technique reliability was good to excellent to study spinal surgery accuracy. Implant deviations should be anticipated when planning stabilization surgery in large breed dogs using the freehand-guided technique.

Haematomyelia and myelomalacia following an inadvertent thoracic intraspinal injection in a cat.

CASE SUMMARY: A 4-month-old cat was presented with acute paraplegia after the referring veterinarian performed a subcutaneous injection (cefovecin and dexamethasone) in the caudodorsal thoracic area, during which the cat suddenly became uncooperative. A complete neurological examination performed 1 day after the injection revealed paraplegia without deep pain perception and reduced segmental spinal reflexes in the pelvic limbs. Findings were consistent with either an L4-S3 myelopathy or a T3-L3 myelopathy with subsequent spinal shock. MRI showed swelling of the spinal cord from T1 to L1 with heterogeneous T2-weighted intramedullary hyperintensity and no contrast enhancement. A centrally located intraspinal signal void was visible in T2*-weighted images. These changes were compatible with a suspected traumatic intraspinal injection. Despite intensive supportive care over 4 days, neurological status did not improve and the cat was euthanased. Gross pathology findings revealed severe intramedullary haemorrhage and myelomalacia in the T10-L1 spinal cord segments. Histopathology of the spinal cord after haematoxylin and eosin staining revealed a severe intramedullary space-occupying haemorrhage with focal malacia. A trajectory-like, optically empty cavity containing some eosinophilic droplets at the edges was detected. Although no further evidence of trauma was noted in the surrounding structures, the spinal cord changes were compatible with a perforating trauma. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first report of thoracic intraspinal injection causing myelomalacia defined by an ante-mortem MRI and confirmed post mortem by histopathology. The traumatic myelopathy appeared to be most compatible with an intraspinal injection causing vascular rupture.

[Diagnostics in epilepsy - potential of magnetic resonance imaging]. / Diagnostik der Epilepsie ­ Möglichkeiten der Magnetresonanztomografie.

Epilepsy is a common neurologic disease frequently encountered by small animal practitioners. The disease comprises a multiplicity of clinical presentations and etiologies and often necessitates a comprehensive as well as cost-intensive diagnostic workup. This is mandatory in order to be able to diagnose or exclude a metabolic cause of the seizures and to distinguish between idiopathic and structural epilepsy. The examination by means of magnetic resonance imaging (MRI) represents a central component of the diagnostic workup, which in turn has essential effects on treatment and prognosis. In order to achieve standardized examination and comparable results, it is of utmost importance to use defined MRI protocols. Accordingly, communication and interaction between clinical institutions may be facilitated and as of yet undetected structural changes might be recorded in future MRI techniques. This review article sets particularly emphasis on the definition and classification of epilepsy as well as its diagnostic imaging procedures and refers to statistics and specialists' recommendations for the diagnostic workup in dogs.

Prognostic Factors in Canine Acute Intervertebral Disc Disease.

Knowledge of the prognosis of acute spinal cord injury is critical to provide appropriate information for clients and make the best treatment choices. Acute intervertebral disc extrusions (IVDE) are a common cause of pain and paralysis in dogs with several types of IVDE occurring. Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Concentration of structural proteins in the plasma, as well as inflammatory mediators, creatine kinase, and myelin basic protein in the cerebrospinal fluid (CSF) can provide additional prognostic information. Finally, cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have been associated with outcome. Future developments in plasma and imaging biomarkers will assist in accurate prognostication and optimization of patient management.

Current Insights Into the Pathology of Canine Intervertebral Disc Extrusion-Induced Spinal Cord Injury.

Spinal cord injury (SCI) in dogs is commonly attributed to intervertebral disc extrusion (IVDE). Over the last years substantial progress was made in the elucidation of factors contributing to the pathogenesis of this common canine disease. A detailed understanding of the underlying histopathological and molecular alterations in the lesioned spinal cord represents a prerequisite to translate knowledge on the time course of secondary injury processes into the clinical setting. This review summarizes the current state of knowledge of the underlying pathology of canine IVDE-related SCI. Pathological alterations in the spinal cord of dogs affected by IVDE-related SCI include early and persisting axonal damage and glial responses, dominated by phagocytic microglia/macrophages. These processes are paralleled by a pro-inflammatory microenvironment with dysregulation of cytokines and matrix metalloproteinases within the spinal cord. These data mirror findings from a clinical and therapeutic perspective and can be used to identify biomarkers that are able to more precisely predict the clinical outcome. The pathogenesis of progressive myelomalacia, a devastating complication of SCI in dogs, is not understood in detail so far; however, a fulminant and exaggerating secondary injury response with massive reactive oxygen species formation seems to be involved in this unique neuropathological entity. There are substantial gaps in the knowledge of pathological changes in IVDE with respect to more advanced and chronic lesions and the potential involvement of demyelination. Moreover, the role of microglia/macrophage polarization in IVDE-related SCI still remains to be investigated. A close collaboration of clinical neurologists and veterinary pathologists will help to facilitate an integrative approach to a more detailed understanding of the molecular pathogenesis of canine IVDE and thus to identify therapeutic targets.

Fractures of the Second Cervical Vertebra in 66 Dogs and 3 Cats: A Retrospective Study.

BACKGROUND: In human medicine, fractures of the second cervical vertebra have been studied elaborately and categorized in detail. This is not the case in veterinary medicine where clinical decisions are often based on old studies focusing on the cervical spine in general. OBJECTIVES: The aim of this study was to describe the clinical features, fracture types, therapeutic options and outcome of dogs and cats with a fractured axis. STUDY DESIGN: The present study was a multi-institutional retrospective case series. RESULTS: Crossbreeds and Labrador Retrievers were the most represented dog breeds. Median age was 2 years. Motor vehicle accident was the most common inciting cause, followed by frontal collision. The most common neurological deficits ranged from cervical pain with or without mild ataxia (22/68) to tetraparesis (28/68) and tetraplegia (11/68). Concerning treatment, 37 of 69 patients underwent surgical fracture stabilization, 27/69 received conservative therapy and 5/69 were immediately euthanatized. Of all treated cases, 52/58 showed ambulatory recovery (23/25 of the conservatively treated and 29/33 of the surgically treated cases), whereby in 40/52 cases full recovery without persisting signs was achieved. CONCLUSIONS: Fractures of the axis commonly occur in young dogs. In many cases, neurological deficits are relatively mild. Generally, animals with a fractured axis have a very good prognosis for functional recovery. The risk of perioperative mortality is considerably lower than previously reported.

ATP13A2 missense variant in Australian Cattle Dogs with late onset neuronal ceroid lipofuscinosis.

The neuronal ceroid lipofuscinoses (NCLs) are lysosomal storage disorders characterized by progressive neurodegeneration and declines in neurological functions. Pathogenic sequence variants in at least 13 genes underlie different forms of NCL, almost all of which are recessively inherited. To date 13 sequence variants in 8 canine orthologs of human NCL genes have been found to occur in 11 dog breeds in which they result in progressive neurological disorders similar to human NCLs. Canine NCLs can serve as models for preclinical evaluation of therapeutic interventions for these disorders. In most NCLs, the onset of neurological signs occurs in childhood, but some forms have adult onsets. Among these is CLN12 disease, also known as Kufor-Rakeb syndrome, PARK9, and spastic paraplegia78. These disorders result from variants in ATP13A2 which encodes a putative transmembrane ion transporter important for lysosomal function. Three Australian Cattle Dogs (a female and two of her offspring) were identified with a progressive neurological disorder with an onset of clinical signs at approximately 6 years of age. The affected dogs exhibited clinical courses and histopathology characteristic of the NCLs. Whole genome sequence analysis of one of these dogs revealed a homozygous c.1118C > T variant in ATP13A2 that predicts a nonconservative p.(Thr373Ile) amino acid substitution. All 3 affected dogs were homozygous for this variant, which was heterozygous in 42 of 394 unaffected Australian Cattle Dogs, the remainder of which were homozygous for the c.1118C allele. The high frequency of the mutant allele in this breed suggests that further screening for this variant should identify additional homozygous dogs and indicates that it would be advisable to perform such screening prior to breeding Australian Cattle Dogs.

The role of diffusion tensor imaging as an objective tool for the assessment of motor function recovery after paraplegia in a naturally-occurring large animal model of spinal cord injury.

BACKGROUND: Traumatic spinal cord injury (SCI) results in sensory and motor function impairment and may cause a substantial social and economic burden. For the implementation of novel treatment strategies, parallel development of objective tools evaluating spinal cord (SC) integrity during motor function recovery (MFR) is needed. Diffusion tensor imaging (DTI) enables in vivo microstructural assessment of SCI. METHODS: In the current study, temporal evolvement of DTI metrics during MFR were examined; therefore, values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured in a population of 17 paraplegic dogs with naturally-occurring acute SCI showing MFR within 4 weeks after surgical decompression and compared to 6 control dogs. MRI scans were performed preoperatively and 12 weeks after MFR was observed. DTI metrics were obtained at the lesion epicentre and one SC segment cranially and caudally. Variance analyses were performed to compare values between evaluated localizations in affected dogs and controls and between time points. Correlations between DTI metrics and clinical scores at follow-up examinations were assessed. RESULTS: Before surgery, FA values at epicentres were higher than caudally (p = 0.0014) and control values (p = 0.0097); ADC values were lower in the epicentre compared to control values (p = 0.0035) and perilesional (p = 0.0448 cranially and p = 0.0433 caudally). In follow-up examinations, no significant differences could be found between DTI values from dogs showing MFR and control dogs. Lower ADC values at epicentres correlated with neurological deficits at follow-up examinations (r = - 0.705; p = 0.0023). CONCLUSIONS: Findings suggest that a tendency to the return of DTI values to the physiological situation after surgical decompression accompanies MFR after SCI in paraplegic dogs. DTI may represent a useful and objective clinical tool for follow-up studies examining in vivo SC recovery in treatment studies.

Development of an International Canine Spinal Cord Injury observational registry: a collaborative data-sharing network to optimize translational studies of SCI.

STUDY DESIGN: Prospective cross-sectional cohort study. OBJECTIVES: The canine spontaneous model of spinal cord injury (SCI) is as an important pre-clinical platform as it recapitulates key facets of human injury in a naturally occurring context. The establishment of an observational canine SCI registry constitutes a key step in performing epidemiologic studies and assessing the impact of therapeutic strategies to enhance translational research. Further, accumulating information on dogs with SCI may contribute to current "big data" approaches to enhance understanding of the disease using heterogeneous multi-institutional, multi-species datasets from both pre-clinical and human studies. SETTING: Multiple veterinary academic institutions across the United States and Europe. METHODS: Common data elements recommended for experimental and human SCI studies were reviewed and adapted for use in a web-based registry, to which all dogs presenting to member veterinary tertiary care facilities were prospectively entered over ~1 year. RESULTS: Analysis of data accumulated during the first year of the registry suggests that 16% of dogs with SCI present with severe, sensorimotor-complete injury and that 15% of cases are seen by a tertiary care facility within 8 h of injury. Similar to the human SCI population, 34% were either overweight or obese. CONCLUSIONS: Severity of injury and timing of presentation suggests that neuroprotective studies using the canine clinical model could be conducted efficiently using a multi-institutional approach. Additionally, pet dogs with SCI experience similar comorbidities to people with SCI, in particular obesity, and could serve as an important model to evaluate the effects of this condition.

Transcranial magnetic motor evoked potentials and magnetic resonance imaging findings in paraplegic dogs with recovery of motor function.

BACKGROUND: Transcranial magnetic motor evoked potentials (TMMEP) are associated with severity of clinical signs and magnetic resonance imaging (MRI) findings in dogs with spinal cord disease. HYPOTHESIS: That in initially paraplegic dogs with thoracolumbar intervertebral disc herniation (IVDH), MRI findings before surgery and TMMEPs obtained after decompressive surgery are associated with long-term neurological status and correlate with each other. ANIMALS: Seventeen client-owned paraplegic dogs with acute thoracolumbar IVDH. METHODS: Prospective observational study. TMMEPs were obtained from pelvic limbs and MRI (3T) of the spinal cord was performed at initial clinical presentation. Follow-up studies were performed ≤ 2 days after reappearance of motor function and 3 months later. Ratios of compression length, intramedullary hyperintensities' length (T2-weighted hyperintensity length ratio [T2WLR]), and lesion extension (T2-weighted-lesion extension ratio) in relation to the length of the 2nd lumbar vertebral body were calculated. RESULTS: TMMEPs could be elicited in 10/17 (59%) dogs at 1st and in 16/17 (94%) dogs at 2nd follow-up. Comparison of TMMEPs of 1st and 2nd follow-up showed significantly increased amplitudes (median from 0.19 to 0.45 mV) and decreased latencies (from 69.38 to 40.26 ms; P = .01 and .001, respectively). At 2nd follow-up latencies were significantly associated with ambulatory status (P = .024). T2WLR obtained before surgery correlated with latencies at 2nd follow-up (P = .04). CONCLUSIONS: TMMEP reflect motor function recovery after severe spinal cord injury.

Generation and characterization of highly purified canine Schwann cells from spinal nerve dorsal roots as potential new candidates for transplantation strategies.

Schwann cells are promising candidates for transplantation strategies in the central nervous system by promoting axonal regeneration. The dog represents a translational model for human spinal cord injury (SCI) for studies with new repair strategies after intervertebral disk herniation (IVDH). To overcome the necessity for an additional surgical procedure, for the first time a protocol for the isolation and purification of canine Schwann cells from spinal nerve biopsies during standard hemilaminectomy in IVDH-affected paraplegic dogs for potential transplantation has been developed. Purity was assessed by flow cytometry. The results were compared with biopsies from dogs without SCI. Within 26 ± 4 days, 90.2 ± 8.8% p75 neurotrophin receptor (p75NTR )-positive cells were achieved in IVDH dogs. The total cell count in acute/subacute and chronic IVDH (acute/subacute: 6.82 ± 6.36 × 106 ; chronic: 2.29 ± 2.00 × 106 ) differed significantly (p = 0.0120) at the potential time point of transplantation. No differences in culture period and purity were detected between dogs with and without IVDH. Despite the small sample size and the altered environment, the isolation of Schwann cells was successful. Negative influences on isolation and purification due to potential pathological changes at the biopsy site of IVDH-diseased dogs were ruled out by comparison of Schwann cell pellets from diseased and control dogs. Finally, the functionality of Schwann cells from dogs with IVDH was outlined in co-culture experiments with canine dorsal root ganglion neurons. In conclusion, nerve root biopsies provide a sufficient number of highly purified and functional Schwann cells within a useful time period for novel therapeutic strategies in dogs with SCI.

Zoonotic intestinal helminths interact with the canine immune system by modulating T cell responses and preventing dendritic cell maturation.

Parasite co-evolution alongside the mammalian immune system gave rise to several modulatory strategies by which they prevent exaggerated pathology and facilitate a longer worm survival. As little is known about the immunoregulatory potential of the zoonotic canine parasites Ancylostoma caninum and Toxocara canis in the natural host, the present study aimed to investigate whether their larval excretory-secretory (ES) products can modulate the canine immune system. We demonstrated TcES to increase the frequency of CD4+ Foxp3high T cells, while both AcES and TcES were associated with elevated Helios expression in Foxp3high lymphocytes. ES products were further capable of inducing IL-10 production by lymphocytes, which was mainly attributed to CD8+ T cells. ES treatment of PBMCs prior to mitogen stimulation inhibited polyclonal proliferation of CD4+ and CD8+ T cells. Moreover, monocyte-derived ES-pulsed dendritic cells reduced upregulation of MHC-II and CD80 in response to lipopolysaccharide. The data showed that regulation of the canine immune system by A. caninum and T. canis larvae comprises the modification of antigen-specific and polyclonal T cell responses and dendritic cell maturation.

Morphologic, phenotypic, and transcriptomic characterization of classically and alternatively activated canine blood-derived macrophages in vitro.

Macrophages are a heterogeneous cell population playing a pivotal role in tissue homeostasis and inflammation, and their phenotype strongly depends on the micromilieu. Despite its increasing importance as a translational animal model for human diseases, there is a considerable gap of knowledge with respect to macrophage polarization in dogs. The present study comprehensively investigated the morphologic, phenotypic, and transcriptomic characteristics of unstimulated (M0), M1- (GM-CSF, LPS, IFNγ-stimulated) and M2- (M-CSF, IL-4-stimulated)-polarized canine blood-derived macrophages in vitro. Scanning electron microscopy revealed distinct morphologies of polarized macrophages with formation of multinucleated cells in M2-macrophages, while immunofluorescence employing literature-based prototype-antibodies against CD16, CD32, iNOS, MHC class II (M1-markers), CD163, CD206, and arginase-1 (M2-markers) demonstrated that only CD206 was able to discriminate M2-macrophages from both other phenotypes, highlighting this molecule as a promising marker for canine M2-macrophages. Global microarray analysis revealed profound changes in the transcriptome of polarized canine macrophages. Functional analysis pointed out that M1-polarization was associated with biological processes such as "respiratory burst", whereas M2-polarization was associated with processes such as "mitosis". Literature-based marker gene selection revealed only minor overlaps in the gene sets of the dog compared to prototype markers of murine and human macrophages. Biomarker selection using supervised clustering suggested latexin (LXN) and membrane-spanning 4-domains, subfamily A, member 2 (MS4A2) to be the most powerful predicting biomarkers for canine M1- and M2-macrophages, respectively. Immunofluorescence for both markers demonstrated expression of both proteins by macrophages in vitro but failed to reveal differences between canine M1 and M2-macrophages. The present study provides a solid basis for future studies upon the role of macrophage polarization in spontaneous diseases of the dog, a species that has emerging importance for translational research.