Interleukin-31 in serum and cerebrospinal fluid of dogs with syringomyelia.

BACKGROUND: Syringomyelia is a spinal cord cavity containing cerebrospinal fluid (CSF)-like fluid. If syringomyelia asymmetrically involves the dorsal horn grey matter of the spinal cord, affected dogs show increased signs of dysesthesia and neuropathic pain, like increased itching behaviour. In the dorsal horn, amongst others, receptors for Interleukin-31 (IL-31) can be found. IL-31 is one of the main cytokines involved in the pathogenesis of pruritus in atopic dermatitis in different species. This study investigates suspected elevated levels of IL-31 in serum and CSF of dogs showing signs of pain or increased itching behaviour related to syringomyelia. The IL-31 were measured in archived samples (52 serum and 35 CSF samples) of dogs with syringomyelia (n = 48), atopic dermatitis (n = 3) and of healthy control dogs (n = 11) using a competitive canine IL-31 ELISA. RESULTS: Mean serum IL-31 level in dogs with syringomyelia was 150.1 pg/ml (n = 39), in dogs with atopic dermatitis 228.3 pg/ml (n = 3) and in healthy dogs 80.7 pg/ml (n = 10). Mean CSF IL-31 value was 146.3 pg/ml (n = 27) in dogs with syringomyelia and 186.2 pg/ml (n = 8) in healthy dogs. Individual patients with syringomyelia (especially dogs with otitis media or otitis media and interna or intervertebral disc herniation) showed high IL-31 levels in serum and CSF samples, but the difference was not statistically significant. IL-31 serum and CSF levels did not differ significantly in dogs with syringomyelia with or without itching behaviour and with or without signs of pain. CONCLUSION: Based on this study, increased IL-31 levels seem not to be correlated with itching behaviour or signs of pain in dogs with syringomyelia, but might be caused by other underlying diseases.

Stability of canine and feline cerebrospinal fluid samples regarding total cell count and cell populations stored in "TransFix®/EDTA CSF sample storage tubes".

BACKGROUND: Because of fast leucocyte degeneration in cerebrospinal fluid (CSF) laboratory examinations of CSF samples should be performed approximately within 30 min after withdrawal. This study examines the storage of canine and feline CSF samples in "TransFix®/EDTA CSF Sample Storage Tubes" (Cytomark, Buckingham, UK) for preventing leucocytes from degeneration, so that routine and flow cytometry examinations are feasible up to 3 days after sampling. RESULTS: After storage in TransFix® tubes, leukocytes could not be adequately stained with Türk's solution and differentiating between erythrocytes and leukocytes was cumbersome. In addition, the cell morphology could not be sufficiently assessed on cytospin preparations because of shrunken leukocytes and indistinct cell nuclei. In contrast, by flow cytometry, a significantly higher cell count was measured over the entire study period in the samples stored in TransFix® tubes compared to the untreated samples. The antibodies (AB) against CD3, CD4 and CD21, against CD11b and against CD45 showed a good binding strength and thus enabled a good differentiation of cell populations. However, after storage in the TransFix® tubes, monocytes were no longer detectable using an AB against CD14. CONCLUSION: Based on these results, "TransFix®/EDTA CSF Sample Storage Tubes" can be used for extended storage prior to flow cytometric analysis of lymphocytes and granulocytes in CSF samples but not for detecting monocytes. However, standard examinations, such as microscopic cell counting and morphological cell assessment should be performed on fresh CSF samples.

Evaluation of IL-1ß levels in epilepsy and traumatic brain injury in dogs.

BACKGROUND: Epilepsy is a common neurological disease in dogs affecting approximately 0.6-0.75% of the canine population. There is much evidence of neuroinflammation presence in epilepsy, creating new possibilities for the treatment of the disease. An increased expression of interleukin-1 beta (IL-1ß) was reported in epileptogenic foci. We hypothesized that there is an elevation of IL-1ß in serum and CSF of dogs with epilepsy, as well as in serum of dogs with TBI, reflecting involvement of this cytokine in pathophysiology of naturally occurring canine epilepsy in a clinical setting. RESULTS: IL-1ß levels were evaluated in CSF and serum of six healthy and 51 dogs with epilepsy (structural and idiopathic). In 16 dogs with TBI, only serum was tested. IL-1ß concentrations in CSF were not detectable. Serum values were not elevated in dogs with TBI in comparison to healthy controls (p > 0.05). However, dogs with epilepsy had increased levels of IL-1ß in serum (p = 0.003) regardless of the underlying cause of the disease (p = 0.0045). There was no significant relationship between the variables and IL-1ß levels. Statistically noticeable (p = 0.0630) was that approximately 10% of dog with epilepsy (R2 = 0.105) had increased seizure frequency and IL-1ß elevation. CONCLUSION: Increased IL-1ß levels were detected in the peripheral blood in dogs with idiopathic and structural epilepsy leading to the assumption that there is an involvement of inflammation in pathophysiology of epilepsy which should be considered in the search for new therapeutic strategies for this disease. However, to better understand the pathogenic role of this cytokine in epilepsy, further evaluation of IL-1ß in brain tissue is desired.

Th17-skewed immune response and cluster of differentiation 40 ligand expression in canine steroid-responsive meningitis-arteritis, a large animal model for neutrophilic meningitis.

BACKGROUND: Steroid-responsive meningitis-arteritis (SRMA) is an immune-mediated disorder characterized by neutrophilic pleocytosis and an arteritis particularly in the cervical leptomeninges. Previous studies of the disease have shown increased levels of IL-6 and TGF-ß1 in cerebrospinal fluid (CSF). In the presence of these cytokines, naive CD4+ cells differentiate into Th17 lymphocytes which synthesize interleukin 17 (IL-17). It has been shown that IL-17 plays an active role in autoimmune diseases, it induces and mediates inflammatory responses and has an important role in recruitment of neutrophils. The hypothesis of a Th17-skewed immune response in SRMA should be supported by evaluating IL-17 and CD40L, inducing the vasculitis. METHODS: An enzyme-linked immunosorbent assay (ELISA) was performed to measure IL-17 and CD40L in serum and CSF from a total of 79 dogs. Measurements of patients suffering from SRMA in the acute state (SRMA A) were compared with levels of patients under treatment with steroids (SRMA T), recurrence of the disease (SRMA R), other neurological disorders, and healthy dogs, using the two-part test. Additionally, secretion of IL-17 and interferon gamma (IFN-γ) from the peripheral blood mononuclear cells (PBMCs) was confirmed by an enzyme-linked immunospot (ELISpot) assay. RESULTS: Significant higher levels of IL-17 were found in CSF of dogs with SRMA A compared with SRMA T, other neurological disorders and healthy dogs (p < 0.0001). In addition, levels of CD40L in CSF in dogs with SRMA A and SRMA R were significantly higher than in those with SRMA T (p = 0.0004) and healthy controls (p = 0.014). Furthermore, CSF concentrations of IL-17 and CD40L showed a strong positive correlation among each other (rSpear = 0.6601; p < 0.0001) and with the degree of pleocytosis (rSpear = 0.8842; p < 0.0001 and rSpear = 0.6649; p < 0.0001, respectively). IL-17 synthesis from PBMCs in SRMA patients was confirmed; however, IL-17 is mainly intrathecally produced. CONCLUSIONS: These results imply that Th17 cells are inducing the autoimmune response in SRMA and are involved in the severe neutrophilic pleocytosis and disruption of the blood-brain barrier (BBB). CD-40L intrathecal synthesis might be involved in the striking vasculitis. The investigation of the role of IL-17 in SRMA might elucidate important pathomechanism and open new therapeutic strategies.

Measurements of C-reactive protein (CRP) and nerve-growth-factor (NGF) concentrations in serum and urine samples of dogs with neurologic disorders.

BACKGROUND: The purpose of this study was to prove the hypothesis that C-reactive protein (CRP) and nerve growth factor (NGF) may be potential biomarkers for lower urinary tract disorders and may be able to distinguish between micturition dysfunctions of different origin in dogs with spinal cord diseases. NGF- and CRP- concentrations were measured in serum and urine samples using specific ELISA-Kits. Results in urine were standardized by urine-creatinine levels. RESULTS: CRP in serum was detectable in 32/76 and in urine samples in 40/76 patients. NGF could be measured in all serum and in 70/76 urine samples. Urinary CRP concentrations were significantly higher in dogs with micturition dysfunction (p = 0.0009) and in dogs with different neurological diseases (p = 0.0020) compared to the control group. However, comparing dogs with spinal cord disorders with and without associated micturition dysfunction no significant difference could be detected for NGF and CRP values in urine or serum samples. Additionally, levels did not decrease significantly, when measured at the time when the dogs regained the ability to urinate properly (urinary NGF p = 0.7962; urinary CRP p = 0.078). Urine samples with bacteria and/or leukocytes had no significant increase in urinary NGF (p = 0.1112) or CRP (p = 0.0534) concentrations, but higher CRP-levels in urine from dogs with cystitis were found compared to dogs without signs of cystitis. CONCLUSIONS: From these data we conclude that neither CRP nor NGF in urine or serum can be considered as reliable biomarkers for micturition disorders in dogs with spinal cord disorders in a clinical setting, but their production might be part of the pathogenesis of such disorders. Significantly higher levels of CRP could be found in the urine of dogs with micturition dysfunctions compared to control dogs. This phenomenon could potentially be explained by unspecific extrahepatic CRP production by smooth muscle cells in the dilated bladder.

MIP-3ß/CCL19 is associated with the intrathecal invasion of mononuclear cells in neuroinflammatory and non-neuroinflammatory CNS diseases in dogs.

BACKGROUND: Chemokines such as MIP-3ß/CCL19 are important factors in the mechanism of cell migration and pathogenesis of central nervous system (CNS) inflammatory reactions. The hypothesis of this study is that CCL19, also known as MIP-3ß, is involved in the pathogenesis of inflammatory and non-inflammatory CNS diseases of dogs. Experiments were performed on cerebrospinal fluid (CSF) and serum samples of dogs affected with steroid responsive meningitis-arteritis (SRMA) during the acute phase as well as during treatment. Dogs with SRMA were compared to dogs with presumed meningoencephalomyelitis of unknown origin (MUO), and both groups sub-categorized into dogs receiving no therapy and with patients receiving prednisolone therapy. Idiopathic epilepsy (IE), a group with normal CSF cell count, was used as a control. Additionally, dogs with intervertebral disc disease (IVDD) of varying severity were analyzed. Chemokine concentrations were determined by enzyme linked immunosorbent assay. Migration assays were performed on seven selected CSF samples using a disposable 96-well chemotaxis chamber. RESULTS: CCL19 was detectable in CSF samples of all dogs. Dogs with untreated SRMA and MUO displayed pronounced CCL19 elevations compared to the control group and patients receiving glucocorticosteroid treatment. CSF cell counts of untreated SRMA and MUO patients were significantly positively correlated with the CCL19 CSF concentration. IVDD patients also had elevated CCL19 concentration compared to controls, but values were considerably lower than in inflammatory CNS diseases. Selected CSF samples displayed chemotactic activity for mononuclear cells in the migration assay. CONCLUSIONS: CCL19 CSF concentrations were markedly elevated in patients affected with the neuroinflammatory diseases SRMA and MUO and showed a strong correlation with the CSF cell count. This chemokine may play an important role in the pathogenesis of SRMA and MUO. The elevation of CSF CCL19 in IVDD suggests that it may also be involved in the secondary wave of spinal cord injuries.

Canine idiopathic generalized tremor syndrome, immune-mediated?

Idiopathic generalized tremor syndrome is a disorder characterized by an acute onset of full-body tremors, sometimes accompanied by vestibulo-cerebellar signs, that is responsive to treatment with corticosteroids. Although considered to have an overall good outcome, relapsing and persistent mild clinical signs have been described. So far, little is known about the etiopathology of this syndrome, but it is believed to have an immune-mediated origin. In human medicine, description of numerous autoantibodies involved in certain non-infectious neurologic disorders has revolutionized understanding of their pathophysiology, diagnosis and treatment. In this multicenter retrospective study, we aimed to describe the clinical signs, course, and outcome of dogs with idiopathic generalized tremor syndrome and correlate potential findings with the presence or absence of autoantibodies associated with autoimmune cerebellar syndromes in humans. Information regarding signalment, history, clinical signs, laboratory findings, diagnostic imaging and testing for regional infectious diseases was gathered and the remaining serum and CSF samples were then analyzed for neural antibodies against targets associated with autoimmune encephalitic diseases of humans. Thirty-three dogs were included, and screening for neural antibodies was performed in 30 of those dogs. The analysis showed an increased titer of mGluR1 antibodies in two dogs, GFAP and later in the course of disease mGluR1 antibodies in one dog and an increase in unspecific autoantibodies which could not be further classified in two dogs. Dogs with detectable neural autoantibodies always had cerebrospinal fluid abnormalities in the form of a pleocytosis, with or without increased protein concentration, and tended to present with hyperthermia, potentially indicating a more severe clinical form of idiopathic generalized tremor syndrome in these cases. In conclusion, idiopathic generalized tremor syndrome is proposed to be an immune-mediated disorder potentially mediated by neural autoantibodies in a subgroup of dogs.

Interleukin-6, vascular endothelial growth factor and transforming growth factor beta 1 in canine steroid responsive meningitis-arteritis.

BACKGROUND: Steroid Responsive Meningitis-Arteritis (SRMA) is a common cause of inflammation of the canine central nervous system (CNS). To investigate if transforming growth factor beta 1 (TGF-ß1), interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) are involved in the production of excessive immunoglobulin A (IgA), the induction of acute phase proteins and in the development of a systemic necrotizing vasculitis, characteristic of SRMA, these three signalling proteins were evaluated. RESULTS: Cerebrospinal fluid (CSF) and serum samples of dogs during the acute phase of SRMA (SRMA) were tested for IL-6, VEGF and TGF- ß1. Results were compared to those of dogs affected with SRMA during treatment (SRMA Th) and during relapse (SRMA R), to dogs with other meningoencephalomyelitides (ME), with miscellaneous non-inflammatory diseases of the CNS (CNS-Mix), with idiopathic epilepsy (IE), with systemic inflammatory diseases (Syst. Infl.) and with healthy dogs (Healthy). Concentrations of IL-6 and VEGF in CSF were significantly elevated in the SRMA group compared to the other disease categories (p<0.05). The CSF concentrations of TGF-ß1 were increased in SRMA group, but statistically significant differences were found only in comparison with Healthy and CNS-Mix groups. No differences were detected in the serum concentrations of TGF-ß1 between the different groups. In untreated SRMA patients, a positive correlation (rSpear = 0.3549; P=0.0337) between concentrations of TGF-ß1 and IgA concentration was found in CSF, while concentrations of IL-6 and VEGF in CSF positively correlated with the degree of pleocytosis (rSpear=0.8323; P<0.0001 and rSpear=0.5711; P=0.0166, respectively). CONCLUSIONS: Our results suggest that these three signalling proteins are biomarkers of disease activity in SRMA. VEGF might play an important role in the development of a systemic arteritis. TGF-ß1 is considered to be involved in the excessive IgA production, while IL-6 in the pleocytosis. The combined intrathecal increase of TGF-ß1 and IL-6 detected in SRMA could possibly force CD4 progenitors to differentiate towards the newly described Th17 lymphocyte subset and enhance the autoimmune response.

The Reibergram for immunoglobulin A in dogs: Evaluation of intrathecal IgA synthesis using a quotient graph in dogs with neurological diseases.

BACKGROUND: Increased cerebrospinal fluid (CSF) protein concentration is a common finding in neurological diseases of dogs. Distinguishing between intrathecally-produced proteins and proteins that have passed the blood-CSF barrier because of barrier disruption facilitates diagnosis. Albumin is a microprotein mainly produced extrathecally that can be used as a reference marker for blood-CSF barrier dysfunction. OBJECTIVES: Develop a quotient graph based on the CSF/serum quotient of albumin and immunoglobulin A (IgA; Reibergram) to visualize intrathecal IgA synthesis and blood-CSF barrier dysfunction. ANIMALS AND METHODS: Retrospective single-center cohort study. A hyperbolic function was developed using data from 6 healthy Beagles and 38 dogs with neurological diseases in which an isolated blood-CSF barrier dysfunction was expected. The function was validated using data from 10 dogs with expected intrathecal IgA synthesis and was visualized as a quotient graph. Finally, the graph was used to evaluate data of 118 dogs with various neurological diseases. RESULTS: Within the Reibergram, the function QLim IgA = 0.13 QAlb 2 + 11.9 · 10 - 6 - 1.01 · 10 - 3 describes the upper values of physiological IgA quotients. It detects diseases with expected intrathecal IgA synthesis with higher sensitivity (85%) and specificity (89%) than the IgA index. The upper value of the physiological albumin quotient is 2.22 and detects diseases with expected blood-CSF barrier dysfunction (sensitivity: 81%; specificity: 88%). CONCLUSION AND CLINICAL IMPORTANCE: The canine Reibergram can detect blood-CSF barrier dysfunction and intrathecal IgA synthesis in the majority of cases. The graphical visualization simplifies data evaluation and makes it a feasible tool in routine CSF diagnostic testing.

Elevated Interleukin-31 Levels in Serum, but Not CSF of Dogs with Steroid-Responsive Meningitis-Arteritis Suggest an Involvement in Its Pathogenesis.

Steroid-responsive meningitis-arteritis (SRMA) is a predominantly Th-2 immune-mediated disease, but the exact pathomechanism remains unclear. Interleukin-31 (IL-31) is predominantly produced by T cells with a Th-2 phenotype during proinflammatory conditions. We hypothesize that IL-31 might be involved in the pathogenesis of SRMA. IL-31 was measured in archived samples (49 serum and 52 CSF samples) of dogs with SRMA, meningoencephalitis of unknown origin (MUO), infectious meningoencephalitis, and atopic dermatitis, and of healthy control dogs using a competitive canine IL-31 ELISA. The mean serum IL-31 level in dogs with SRMA (n = 18) was mildly higher compared to dogs with atopic dermatitis (n = 3, p = 0.8135) and MUO (n = 15, p = 0.7618) and markedly higher than in healthy controls (n = 10, p = 0.1327) and dogs with infectious meningoencephalitis (n = 3, no statistics). Dogs with SRMA in the acute stage of the disease and without any pre-treatment had the highest IL-31 levels. The mean CSF IL-31 value for dogs with SRMA (n = 23) was quite similar to that for healthy controls (n = 8, p = 0.4454) and did not differ markedly from dogs with MUO (n = 19, p = 0.8724) and infectious meningoencephalitis. Based on this study, an involvement of IL-31 in the pathogenesis of the systemic Th-2 immune-mediated immune response in SRMA can be assumed as a further component leading to an aberrant immune reaction.

Toll-like receptors 4 and 9 are responsible for the maintenance of the inflammatory reaction in canine steroid-responsive meningitis-arteritis, a large animal model for neutrophilic meningitis.

BACKGROUND: Steroid-responsive meningitis-arteritis (SRMA) is a systemic inflammatory disease affecting young adult dogs and a potential large animal model for neutrophilic meningitis. Similarities between SRMA and infectious central nervous system (CNS) diseases in lymphocyte subsets suggest an infectious origin.Toll-like receptors (TLRs) are pattern recognition receptors playing an important role in innate immunity. Due to their ability to recognize both self and non-self antigens, we hypothesize that TLRs are among the key factors for the induction of the inflammatory process in SRMA and provide an indirect hint on the etiology of the disease. METHODS: The expression profile of cell surface TLRs (TLR2, TLR4 and TLR5) and intracellular TLRs (TLR3 and TLR9) of canine leukocytes was analyzed by immunophenotyping and subsequent flow cytometric measurements. Experiments were performed on cerebrospinal fluid (CSF) and peripheral blood (PB) samples of dogs affected with SRMA during the acute phase (n = 14) as well as during treatment (n = 23) and compared with those of dogs with bacterial meningitis (n = 3), meningoencephalitis of unknown etiology (n = 6), neoplasia of the central nervous system (n = 6) and a group of dogs with miscellaneous neurological diseases (n = 9). Two additional control groups consisted of dogs with pyogenic infections (n = 13) and of healthy dogs (n = 6). RESULTS: All examined groups showed a high percentage of TLR2, TLR4 and TLR5 positive PB polymorphonuclear cells (PMNs) in comparison to healthy dogs. Very high values of TLR9 positive PB PMNs were detected in acute SRMA. Only a few similarities were found between SRMA patients and dogs with pyogenic infections, both groups were characterized by high expression of TLR4 positive PB monocytes. Glucocorticosteroid therapy reduced TLR2, TLR4 and TLR9 expression in PB monocytes. CONCLUSIONS: A relatively high expression of TLR4 and TLR9 in acute SRMA suggests that these two receptors might be involved in the inflammatory process in SRMA, enhancing the autoimmune reaction. Systematic CSF cell analysis for TLRs can be performed in future treatment studies in larger animals, such as dogs.

Th17 cell-mediated immune response in a subpopulation of dogs with idiopathic epilepsy.

BACKGROUND: Canine idiopathic epilepsy (IE) is a common neurological disease with severe impact on the owner´s and the dog's quality of life. A subpopulation of dogs with IE does not respond to antiseizure drugs (non-responder). Th17 cells (T helper cells) and their proinflammatory Interleukin-17 (IL-17) are part of the immune system and previous studies showed their involvement in the pathogenesis of several autoimmune diseases. Non-responder might have an abnormal immune response against structures of the central nervous system. To discover a new aetiology of canine IE and thereby optimising the therapy of intractable IE, this prospective study aimed to investigate Th17 cells and IL-17 in dogs with IE. The underlying hypothesis was that in some dogs with IE a Th17 cell-mediated immune response could be detectable. METHODS: 57 dogs with IE and 10 healthy dogs (control group, C) were enrolled in the study. EDTA blood was taken to measure Th17 cells by flow cytometry. IL-17 was measured in 35 cerebrospinal fluid (CSF) and 33 serum samples using an enzyme-linked immunosorbent assay (ELISA). It was investigated whether there was a significant increase of stimulated Th17 cells in blood samples or of IL-17 in serum and CSF samples of dogs with IE in comparison to C. Correlations between the amount of Th17 cells/µL or IL-17 and different clinical parameters e.g. seizure frequency, seizure type, seizure severity or treatment response were evaluated. Additionally, Th17 cells/µL were randomly controlled of 17 dogs with IE and were examined for changes over time and in relation to treatment response. RESULTS: Ten dogs with IE had strongly elevated stimulated Th17 cells/µL within the blood (>100 Th17 cells/µL). A slight positive correlation between stimulated Th17 cells/µL and seizure severity (p = 0.046; rSpear = 0.27) was proven in these dogs. In addition, 4/10 dogs with elevated Th17 levels experienced cluster seizures and status epilepticus in comparison to 9% of the dogs with non-elevated Th17 levels (<100 Th17 cells/µL). Dogs with IE had significantly higher IL-17 values in CSF and serum samples compared to C (p<0.001; p<0.002; respectively). CONCLUSION: In single dogs with IE, strongly increased amounts of Th17 cells were detectable and dogs with elevated Th17 cells seemed to have a greater risk for experiencing a combination of cluster seizures and status epilepticus. Therefore, an underlying Th17-cell mediated immune response was suspected and hence anti-inflammatory drugs could be indicated in these single cases with intractable epilepsy.

Evaluation of the involvement of Th17-cells in the pathogenesis of canine spinal cord injury.

Intervertebral disc herniation (IVDH) is a frequently occurring neurological disease of dogs and the most common reason for spinal cord injury (SCI). Clinical signs are variable thus a reliable prognosis is crucial for further treatment decisions. Currently, the prognosis of IVDH primarily depends on presence or absence of deep pain perception. The purpose of this study was to investigate if Th17-cells could serve as a potential, prognostic biomarker for IVDH. We investigated a possible role of the adaptive immune system in the pathophysiology of IVDH in dogs. The investigation was performed by analyzing the influence of Th17-cells in blood and cerebrospinal fluid (CSF) of sixty-two dogs suffering from IVDH. In addition, we examined if Th17-cells might influence the course of this disease. As controls, paired blood and CSF samples of ten healthy clinic-owned dogs were examined and the values were compared to those of the IVDH group. Isolated lymphocytes were analyzed after stimulation by using multicolour flow cytometry to measure the number of Th17-cells. IL-17 levels were measured in paired serum and CSF samples by Enzyme-linked Immunosorbent Assays (ELISA). Highly significant differences of stimulated Th17-cells in EDTA-blood samples could be determined between Th17-cell levels of dogs suffering from IVDH and the healthy control group and also between three sampling time points: preoperative, after clinical improvement and after six months. Preoperatively, Th17-cell levels were strongly decreased in contrast to the healthy controls. The decreased amount of Th17-cell levels recovered postoperatively so that Th17-cell levels of the last follow-up examinations were comparable to the control group after six months. At the same time IL-17 measured in serum preoperatively was significantly higher in dogs with IVDH than in healthy controls. However, there was no considerable difference of IL-17 measured in CSF between the groups. In conclusion, a high activity and consequent consumption of IL-17-producing Th17-cells is suspected in acute IVDH. These findings may indicate an involvement of Th17-cells in the pathogenesis of IVDH and emphasize that these cells might be involved in the interaction of pain, stress and immune reaction. However, based on the findings of this study the development of Th17-cells as a biomarker cannot be recommended, yet.

Measurement of Neutrophil Gelatinase-Associated Lipocalin Concentration in Canine Cerebrospinal Fluid and Serum and Its Involvement in Neuroinflammation.

Neutrophil gelatinase-associated Lipocalin (NGAL) is a glycoprotein involved in inflammation acting as an acute phase protein and chemokine as well as a regulator of iron homeostasis. NGAL has been shown to be upregulated in experimental autoimmune encephalomyelitis (EAE) in mice. Increased NGAL concentration in cerebrospinal fluid (CSF) and expression in central nervous system (CNS) has been described in human neuroinflammatory disease such as multiple sclerosis and neuropsychiatric lupus as well as in bacterial meningitis. We aimed to investigate involvement of NGAL in spontaneous canine neuroinflammation as a potential large animal model for immune- mediated neurological disorders. A commercially available Enzyme-linked Immunosorbent Assay (ELISA) for detection of canine NGAL was validated for use in canine CSF. Concentration in CSF and serum of canine patients suffering from steroid- responsive meningitis- arteriitis (SRMA), Meningoencephalitis of unknown origin (MUO), different non- inflammatory CNS disease and control dogs were compared. Relationship between NGAL concentration in CSF and serum and inflammatory parameters in CSF and blood (IgA concentration, total nucleated cell count (TNCC), protein content) as well as association with erythrocytes in CSF, duration of illness, plasma creatinine and urinary leucocytes were evaluated. In dogs with SRMA and MUO, CSF concentration of NGAL was significantly higher than in dogs with idiopathic epilepsy, compressive myelopathy, intracranial neoplasia and SRMA in remission (p < 0.0001). Patients with acute SRMA had significantly higher levels of NGAL in CSF than neurologically normal controls (p < 0.0001). Serum NGAL concentrations were significantly higher in dogs with SRMA than in patients with myelopathy and intracranial neoplasia (p < 0.0001). NGAL levels in CSF were strongly positively associated with IgA concentration (rSpear= 0.60116, p < 0.0001), TNCC (rSpear= 0.65746, p < 0.0001) and protein content (rSpear= 0.73353, p < 0.0001) in CSF. It can be measured in CSF of healthy and diseased dogs. Higher concentrations in canine patients with SRMA as well as positive association with TNCC in CSF suggest an involvement in pro-inflammatory pathways and chemotaxis in SRMA. High serum levels of NGAL in serum of SRMA patients in different stages of disease might reflect the systemic character of the disease.

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.

Passage-dependent morphological and phenotypical changes of a canine histiocytic sarcoma cell line (DH82 cells).

DH82 cells represent a permanent macrophage cell line isolated from a dog with histiocytic sarcoma (HS) and are commonly used in various fields of research upon infection and cancer, respectively. Despite its frequent use, data on cell surface antigen expression of this cell line are fragmentary and in part inconsistent. We therefore aimed at a detailed morphological and antigenic characterization of DH82 cells with respect to passage-dependent differences. Cellular morphology of early (≤ 13) and late (≥ 66) passages of DH82 cells was evaluated via scanning electron microscopy. Moreover, cells were labelled with 10 monoclonal antibodies directed against CD11c, CD14, CD18, CD44, CD45, CD80, CD86, MHC-I, MHC-II, and ICAM-1 for flow cytometric analysis. Early passage cells were characterized by round cell bodies with abundant small cytoplasmic projections whereas later passages exhibited a spindle-shaped morphology with large processes. The percentage of CD11c-, CD14-, CD18-, CD45-, and CD80 positive cells significantly decreased in late passages whereas the expression of CD44, CD86, MHC-I, MHC-II and ICAM-1 remained unchanged. DH82 cells represent a remarkably heterogeneous cell line with divergent antigenic and morphologic properties. The present findings have important implications for future studies, which should consider distinct characteristics with regard to the used passage.

Microglial ROS production in an electrical rat post-status epilepticus model of epileptogenesis.

Reactive oxygen species and inflammatory signaling have been identified as pivotal pathophysiological factors contributing to epileptogenesis. Considering the development of combined anti-inflammatory and antioxidant treatment strategies with antiepileptogenic potential, a characterization of the time course of microglial reactive oxygen species generation during epileptogenesis is of major interest. Thus, we isolated microglia cells and analyzed the generation of reactive oxygen species by flow cytometric analysis in an electrical rat post-status epilepticus model. Two days post status epilepticus, a large-sized cell cluster exhibited a pronounced response with excessive production of reactive oxygen species upon stimulation with phorbol-myristate-acetate. Neither in the latency phase nor in the chronic phase with spontaneous seizures a comparable cell population with induction of reactive oxygen species was identified. We were able to demonstrate in the electrical rat post-status-epilepticus model, that microglial ROS generation reaches a peak after the initial insult, is only marginally increased in the latency phase, and returns to control levels during the chronic epileptic phase. The data suggest that a combination of anti-inflammatory and radical scavenging approaches might only be beneficial during a short time window after an epileptogenic brain insult.

Immunophenotyping of immune cell populations in the raccoon (Procyon lotor).

The raccoon (Procyon lotor) is a highly adaptable carnivore that has rapidly conquered Europe over the last decades and represents a potential candidate as pathogen reservoir, bearing the risk for transmission of infectious agents, as zoonosis or spill-over, to other wild life and domestic animals and man. Comprehensive investigations of infectious diseases in raccoons require a detailed knowledge of the participating immune cell populations. To close this gap of knowledge, various antibodies were tested for cross-reactivity with leukocytes in lymphoid organs and peripheral blood of raccoons using immunohistochemistry and flow cytometry, respectively. Eight out of 16 antibodies, directed against CD3, CD79α, Pax-5, IgG, CD44, MHC class II, myeloid/histiocyte antigen (MAC387), and Iba-1 exhibited a specific immunoreaction with cells in distinct anatomical compartments in formalin-fixed paraffin-embedded lymphoid tissues. Flow cytometric analysis revealed that 7 out of 18 antibodies directed against CD11c, CD14, CD21, CD44, CD79α, MHC class I and II cross-reacted with peripheral blood-derived raccoon leukocytes. Summarized, the usefulness of several cross-reacting antibodies was determined for the characterization of raccoon immune cells in immunohistochemistry and flow cytometry, offering the opportunity to study the raccoon immune system under normal and diseased conditions.

Measurement of phagocytosis and oxidative burst of canine neutrophils: high variation in healthy dogs.

Quantitative analysis of phagocytosis and oxidative burst in canine polymorphonuclear (PMN) cells was performed by flow cytometry techniques. Different concentrations of phorbol myristate acetate (PMA) were used to modulate PMN phagocytosis. A low concentration of PMA (3 nmol) resulted in increased phagocytic activity of canine PMN, which could not be enhanced by higher dosages. Experiments with a reference cell population showed high losses of PMN, most probably by adherence to plastic material. It was possible to avoid this loss by layering all ingredients on cushions of Histopaque. However, Histopaque had a negative influence on the phagocytic activity of canine PMN. The use of PMA led to a dosage-dependent increase in the oxidative burst measured by the production of reactive oxygen species (ROS). Cushions of Histopaque were used to avoid cell loss. There was no negative influence of Histopaque on ROS formation. Storage of canine PMN for 24 h at room temperature had no negative influence on phagocytosis or oxidative burst measurements. Variations in the ROS assays conducted by two different examiners could be eliminated by use of a Histopaque-cushion.

Evaluation of stem cell marker gene expression in canine prostate carcinoma- and prostate cyst-derived cell lines.

BACKGROUND/AIM: In human prostate cancer cells with a stem cell-like character (cancer stem cells, CSC) are considered to play a major role in disease development, progression and relapse. Aim of the study was to evaluate if similar cells are present and active in canine prostate cancer providing a naturally-occurring mammalian model for the development of therapeutic approaches targeting CSC. MATERIALS AND METHODS: Stem cell marker expression of CD133, CD44, C-KIT, CD34, ITGA6, OCT4, DDX5 and MELK in canine prostate carcinomas and prostate cyst cell lines were screened by Polymerase Chain Reaction (PCR), quantitative Polymerase Chain Reaction (qPCR) and partially analysed by flow cytometry. RESULTS: Marker analyses by PCR and qPCR, revealed a complex expression pattern for the analysed marker genes, providing a characteristic marker pattern for the studied cell lines. Thereby CD44, CD133, ITGA6 and DDX5 showed the most prominent expression in the analysed cell lines. CONCLUSION: The results revealed a characteristic stem cell marker expression in the analysed cell lines, indicating the presence of CSC in canine prostate cancer.