Further characterization of clinical and laboratory features in VEXAS syndrome: large-scale analysis of a multicentre case series of 116 French patients.

BACKGROUND: A new autoinflammatory syndrome related to somatic mutations of UBA1 was recently described and called VEXAS syndrome ('Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic syndrome'). OBJECTIVES: To describe clinical characteristics, laboratory findings and outcomes of VEXAS syndrome. METHODS: One hundred and sixteen patients with VEXAS syndrome were referred to a French multicentre registry between November 2020 and May 2021. The frequency and median of parameters and vital status, from diagnosis to the end of the follow-up, were recorded. RESULTS: The main clinical features of VEXAS syndrome were found to be skin lesions (83%), noninfectious fever (64%), weight loss (62%), lung involvement (50%), ocular symptoms (39%), relapsing chondritis (36%), venous thrombosis (35%), lymph nodes (34%) and arthralgia (27%). Haematological disease was present in 58 cases (50%): myelodysplastic syndrome (MDS; n = 58) and monoclonal gammopathy of unknown significance (n = 12; all patients with MGUS also have a MDS). UBA1 mutations included p.M41T (45%), p.M41V (30%), p.M41L (18%) and splice mutations (7%). After a median follow-up of 3 years, 18 patients died (15·5%; nine of infection and three due to MDS progression). Unsupervised analysis identified three clusters: cluster 1 (47%; mild-to-moderate disease); cluster 2 (16%; underlying MDS and higher mortality rates); and cluster 3 (37%; constitutional manifestations, higher C-reactive protein levels and less frequent chondritis). The 5-year probability of survival was 84·2% in cluster 1, 50·5% in cluster 2 and 89·6% in cluster 3. The UBA1 p.Met41Leu mutation was associated with a better prognosis. CONCLUSIONS: VEXAS syndrome has a large spectrum of organ manifestations and shows different clinical and prognostic profiles. It also raises a potential impact of the identified UBA1 mutation.

Prolonged hyperinsulinemia increases the production of inflammatory cytokines in equine digital lamellae but not in striated muscle.

Hyperinsulinemia is the key feature of equine metabolic syndrome (EMS) which leads to debilitating sequelae. Hyperinsulinemia-associated laminitis (HAL) is one of the major sequelae of EMS, although the pathophysiological mechanisms are not well elucidated. Using an equine model, we hypothesized that expression of inflammatory markers would be increased in digital lamellae and striated muscle following prolonged hyperinsulinemia. Healthy Standardbred horses (5.4 ± 1.9 years) were alternately assigned to a prolonged euglycemic-hyperinsulinemic clamp (pEHC) or control group (n = 4 per group). Following a 48 h pEHC or a 48 h infusion of a balanced electrolyte solution (controls), biopsies were collected from digital lamellar tissue, skeletal muscle and cardiac muscle were obtained. All hyperinsulinemic horses developed laminitis regardless of previous health status at enrollment. Protein expression was quantified via Western blotting. A significant (P < 0.05) upregulation of the protein expression of heat shock protein 90 (HSP90), alpha 2 macroglobulin (A2M) and fibrinogen (α, ß isoforms), as well as inflammatory cytokines including interleukin-1ß were detected in digital lamellae following prolonged hyperinsulinemia. In contrast, protein expression of cytokines and acute phase proteins in heart and skeletal muscle was unchanged following hyperinsulinemia. Upregulation of inflammatory cytokines and acute phase proteins in digital lamellae during prolonged hyperinsulinemia may reveal potential biomarkers and novel therapeutic targets for equine endocrinopathic laminitis. Further, the lack of increase of inflammatory proteins and acute phase proteins in striated muscle following prolonged hyperinsulinemia may highlight potential anti-inflammatory and cardioprotective mechanisms in these insulin-sensitive tissues.

Naturally occurring compensated insulin resistance selectively alters glucose transporters in visceral and subcutaneous adipose tissues without change in AS160 activation.

Although the importance of adipose tissue (AT) glucose transport in regulating whole-body insulin sensitivity is becoming increasingly evident and insulin resistance (IR) has been widely recognized, the underlying mechanisms of IR are still not well understood. The purpose of the present study was to determine the early pathological changes in glucose transport by characterizing the alterations in glucose transporters (GLUT) in multiple visceral and subcutaneous adipose depots in a large animal model of naturally occurring compensated IR. AT biopsies were collected from horses, which were classified as insulin-sensitive (IS) or compensated IR based on the results of an insulin-modified frequently sampled intravenous glucose tolerance test. Protein expression of GLUT4 (major isoform) and GLUT12 (one of the most recently discovered isoforms) were measured by Western blotting in multiple AT depots, as well as AS160 (a potential key player in GLUT trafficking pathway). Using a biotinylated bis-mannose photolabeled technique, active cell surface GLUT content was quantified. Omental AT had the highest total GLUT content compared to other sites during the IS state. IR was associated with a significantly reduced total GLUT4 content in omental AT, without a change in content in other visceral or subcutaneous adipose sites. In addition, active cell surface GLUT-4, but not -12, was significantly lower in AT of IR compared to IS horses, without change in AS160 phosphorylation between groups. Our data suggest that GLUT4, but not GLUT12, is a pathogenic factor in AT during naturally occurring compensated IR, despite normal AS160 activation.

Diagnostic utility of computed tomography imaging in equine intracranial conditions.

REASONS FOR PERFORMING STUDY: The use of computer tomography (CT) and contrast-enhanced CT (CCT) to image the head is common. However, the validity of CT as a neurodiagnostic indicator of intracranial diseases in horses is unknown. OBJECTIVE: To define the validity of CT and CCT in horses with suspected intracranial disorders. METHODS: The validity of CT imaging was estimated by comparing clinical, clinicopathological and histopathological findings to CT findings in 15 horses presented for intracranial disorders, for which pre- and post contrast CT images and post mortem examination of the brain and skull were reviewed. Post mortem examination (gross and histopathological examination) was considered as the gold standard; and sensitivity, specificity, predictive values, likelihood ratios, and pre- and post test probabilities were calculated. RESULTS: All horses had abnormal neurological examinations on admission. Computer tomography imaging identified intracranial lesions in 8 horses, and included masses (oligodendroglioma, adenocarcinoma and cholesterinic granulomas), acute haemorrhage and skull fractures. Computer tomography imaging failed to identify intracranial lesions in 6 cases, which included meningitis, meningoencephalitis and nonacute haemorrhage. Lesions not recognised by CT were also not evident on gross examination but were identified by histopathological examination of the brain. Post mortem examination of the brain and skull was unremarkable in one horse, for which cranial CT imaging was normal (specificity, 100%). Therefore, the odds of having an intracranial lesion after an abnormal CT were very high. In contrast, there was a moderate sensitivity (57.1%, 95% confidence interval: 29.6-81.2). CONCLUSIONS AND POTENTIAL RELEVANCE: CT was an excellent neurodiagnostic tool in identifying skull fractures, intracranial space-occupying lesions (e.g. neoplasia) and acute haemorrhage and allows to rule in intracranial disorders. However, CT showed limited sensitivity in identifying inflammatory disorders and small parenchymal lesions in the equine brain, which was not further detectable after contrast administration.

[Treatment of ITP and AIHA in CVID: A systematic literature review]. / Traitement du PTI et de l'AHAI au cours du DICV : revue systématique de la littérature.

INTRODUCTION: Ten to 15% of common variable immunodeficiencies (CVID) develop auto-immune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Treatment is based on immunosuppressants, which produce blocking effects in the CVID. Our objective was to assess their risk-benefit ratio in these immunocompromised patients. METHODS: We identified 17 articles detailing the treatment of AIHA and/or ITP in patients suffering from CVID through a systematic review of the MEDLINE database. RESULTS: The increased infectious risk with corticosteroids does not call into question their place in the first line of treatment of ITP and AIHA in CVID. High-doses immunoglobulin therapy remain reserved for ITP with a high risk of bleeding. In second-line treatment, rituximab appears to be effective, with a lower infectious risk than the splenectomy. Immunosuppressants (azathioprine, methotrexate, mycophenolate, cyclophosphamide, vincristine, ciclosporine) are moderately effective and often lead to severe infections, meaning that their use is justified only in resistant cases and steroid-sparing. Dapsone, danazol and anti-D immunoglobulins have an unfavorable risk-benefit ratio. The place of TPO receptor agonists is still to be defined. The establishment of immunoglobulin replacement in the place of immunosuppressants (except for short-term corticotherapy) or splenectomy appears to be essential to limit the risk of infections, including in the absence of previous infections. CONCLUSION: The presence of CVID does not mean that it is necessary to give up on corticosteroids as a first-line treatment and rituximab as a second-line treatment for AIHA and ITP, but it should be in addition to immunoglobulin replacement. A splenectomy should be reserved as a third-line treatment.

The plateau outward current in canine ventricle, sensitive to 4-aminopyridine, is a constitutive contributor to ventricular repolarization.

BACKGROUND AND PURPOSE: I(Kur) (Ultra-rapid delayed rectifier current) has microM sensitivity to 4-aminopyridine (4-AP) and is an important modulator of the plateau amplitude and action potential duration in canine atria. Kv1.5 encodes I(Kur) and is present in both atria and ventricles in canines and humans. We hypothesized that a similar plateau outward current with microM sensitivity to 4-AP is present in canine ventricle. EXPERIMENTAL APPROACH: We used established voltage clamp protocols and used 4-AP (50 and 100 microM) to measure a plateau outward current in normal canine myocytes isolated from the left ventricular mid-myocardium. KEY RESULTS: Action potential recordings in the presence of 4-AP showed significant prolongation of action potential duration at 50 and 90% repolarization at 0.5 and 1 Hz (P<0.05), while no prolongation occurred at 2 Hz. Voltage clamp experiments revealed a rapidly activating current, similar to current characteristics of canine atrial I(Kur), in approximately 70% of left ventricular myocytes. The IC(50) of 4-AP for this current was 24.2 microM. The concentration of 4-AP used in our experiments resulted in selective blockade of an outward current that was not I(to) or I(Kr). Beta-adrenergic stimulation with isoprenaline significantly increased the 4-AP sensitive outward current density (P<0.05), suggesting a role for this current during increased sympathetic stimulation. In silico incorporation into a canine ventricular cell model revealed selective AP prolongation after current blockade. CONCLUSIONS AND IMPLICATIONS: Our results support the existence of a canine ventricular plateau outward current sensitive to micromolar 4-AP and its constitutive role in ventricular repolarization.

Prolonged hyperinsulinemia affects metabolic signal transduction markers in a tissue specific manner.

Insulin dysregulation is common in horses although the mechanisms of metabolic dysfunction are poorly understood. We hypothesized that insulin signaling in striated (cardiac and skeletal) muscle and lamellae may be mediated through different receptors as a result of receptor content, and that transcriptional regulation of downstream signal transduction and glucose transport may also differ between tissues sites during hyperinsulinemia. Archived samples from horses treated with a prolonged insulin infusion or a balanced electrolyte solution were used. All treated horses developed marked hyperinsulinemia and clinical laminitis. Protein expression was compared across tissues for the insulin receptor and insulin-like growth factor 1 receptor (IGF-1R) by immunoblotting. Gene expression of metabolic insulin-signaling markers (insulin receptor substrate 1, Akt2, and glycogen synthase kinase 3 beta [GSK-3ß]) and glucose transport (basal glucose transporter 1 and insulin-sensitive glucose transporter 4) was evaluated using real-time reverse transcription polymerase chain reaction. Lamellar tissue contained significantly more IGF-1R protein than skeletal muscle, indicating the potential significance of IGF-1R signaling for this tissue. Gene expression of the selected markers of insulin signaling and glucose transport in skeletal muscle and lamellar tissues was unaffected by prolonged hyperinsulinemia. In contrast, the significant upregulation of Akt2, GSK-3ß, GLUT1, and GLUT4 gene expression in cardiac tissue suggested that the prolonged hyperinsulinemia induced an increase in insulin sensitivity and a transcriptional activation of glucose transport. Responses to insulin are tissue-specific, and extrapolation of data across tissue sites is inappropriate.

AICAR administration affects glucose metabolism by upregulating the novel glucose transporter, GLUT8, in equine skeletal muscle.

Equine metabolic syndrome is characterized by obesity and insulin resistance (IR). Currently, there is no effective pharmacological treatment for this insidious disease. Glucose uptake is mediated by a family of glucose transporters (GLUT), and is regulated by insulin-dependent and -independent pathways, including 5-AMP-activated protein kinase (AMPK). Importantly, the activation of AMPK, by 5-aminoimidazole-4-carboxamide-1-D-ribofuranoside (AICAR) stimulates glucose uptake in both healthy and diabetic humans. However, whether AICAR promotes glucose uptake in horses has not been established. It is hypothesized that AICAR administration would enhance glucose transport in equine skeletal muscle through AMPK activation. In this study, the effect of an intravenous AICAR infusion on blood glucose and insulin concentrations, as well as on GLUT expression and AMPK activation in equine skeletal muscle (quantified by Western blotting) was examined. Upon administration, plasma AICAR rapidly reached peak concentration. Treatment with AICAR resulted in a decrease (P <0.05) in blood glucose and an increase (P <0.05) in insulin concentration without a change in lactate concentration. The ratio of phosphorylated to total AMPK was increased (P <0.05) in skeletal muscle. While GLUT4 and GLUT1 protein expression remained unchanged, GLUT8 was increased (P <0.05) following AICAR treatment. Up-regulation of GLUT8 protein expression by AICAR suggests that this novel GLUT isoform plays an important role in equine muscle glucose transport. In addition, the data suggest that AMPK activation enhances pancreatic insulin secretion. Collectively, the findings suggest that AICAR acutely promotes muscle glucose uptake in healthy horses and thus its therapeutic potential for managing IR requires investigation.

The impact of prolonged hyperinsulinaemia on glucose transport in equine skeletal muscle and digital lamellae.

REASONS FOR PERFORMING STUDY: An increased incidence of metabolic disease in horses has led to heightened recognition of the pathological consequences of insulin resistance. Laminitis, failure of the weightbearing digital lamellae, is an important consequence. Altered trafficking of specialised glucose transporters (GLUTs), responsible for glucose uptake, is central to the dysregulation of glucose metabolism and may play a role in the pathophysiology of laminitis. OBJECTIVES: We hypothesised that prolonged hyperinsulinaemia alters the regulation of glucose transport in insulin-sensitive tissue and digital lamellae. Our objectives were to compare the relative protein expression of major GLUT isoforms in striated muscle and digital lamellae in healthy horses and during marked and moderate hyperinsulinaemia. STUDY DESIGN: Randomised, controlled study. METHODS: Prolonged hyperinsulinaemia and lamellar damage were induced by a prolonged euglycaemic-hyperinsulinaemic clamp or a prolonged glucose infusion, and results were compared with those of electrolyte-treated control animals. Protein expression of GLUTs was examined with immunoblotting. RESULTS: Lamellar tissue contained more GLUT1 protein than skeletal muscle (P = 0.002) and less GLUT4 than the heart (P = 0.037). During marked hyperinsulinaemia and acute laminitis (induced by the prolonged euglycaemic-hyperinsulinaemic clamp), GLUT1 protein expression was decreased in skeletal muscle (P = 0.029) but unchanged in the lamellae, while novel GLUTs (8 and 12) were increased in the lamellae (P = 0.03) but not in skeletal muscle. However, moderate hyperinsulinaemia and subclinical laminitis (induced by the prolonged glucose infusion) did not cause differential GLUT protein expression in the lamellae compared with control horses. CONCLUSIONS: The results suggest that lamellar tissue functions independently of insulin and that insulin resistance may not be an essential component of the aetiology of laminitis. Marked differences in GLUT expression exist between insulin-sensitive and insulin-independent tissues during metabolic dysfunction in horses. The different expression profiles of novel GLUTs during acute and subclinical laminitis may be important to disease pathophysiology and require further investigation.

Muscle glycogen depletion and subsequent replenishment affect anaerobic capacity of horses.

The purpose of this study was to determine the effect of muscle glycogen depletion and subsequent replenishment on anaerobic capacity of horses. In a blinded crossover study, seven fit horses performed glycogen-depleting exercise on two occasions. Horses were infused after glycogen-depleting exercise with either 6 g/kg body wt of glucose as a 13.5% solution in 0.9% NaCl (Glu) or with 0.9% NaCl (Sal) of equivalent volume. Subsequently, horses performed a high-speed exercise test (120% of maximal rate of oxygen consumption) to estimate maximum accumulated oxygen deficit. Replenishment of muscle glycogen was greater (P < 0.05) in Glu [from 24.7 +/- 7.2 (SE) to 116.5 +/- 7 mmol/kg wet wt before and after infusion, respectively] than in Sal (from 23.4 +/- 7.2 to 47.8 +/- 5.7 mmol/kg wet wt before and after infusion, respectively). Run time to fatigue during the high-speed exercise test (97.3 +/- 8.2 and 70.8 +/- 8.3 s, P < 0.05), maximal accumulated oxygen deficit (105.7 +/- 9.3 and 82.4 +/- 10.3 ml O(2) equivalent/kg, P < 0.05), and blood lactate concentration at the end of the high-speed exercise test (11.1 +/- 1.4 and 9.2 +/- 3.7 mmol/l, P < 0.05) were greater for Glu than for Sal, respectively. We concluded that decreased availability of skeletal muscle glycogen stores diminishes anaerobic power generation and capacity for high-intensity exercise in horses.

The bridging lateral mandibular reconstruction plate revisited.

BACKGROUND: Lateral oromandibular reconstruction using a soft tissue free flap with a first-generation locking mandibular reconstruction plate (MRP) was rejected in a previous series by the senior author (K.E.B.) owing to a high incidence of delayed plate extrusion through the cheek skin. OBJECTIVE: To reexamine this method of reconstruction using a second-generation, low-profile MRP. PATIENTS AND DESIGN: A prospective case series of 27 patients with segmental defects of the lateral mandible after treatment of head and neck cancer. SETTING: An academic tertiary care referral center. INTERVENTION: All patients had mandibular continuity restored using the Leibinger Locking System (Stryker Leibinger Inc, Kalamazoo, Mich) MRP. Associated soft tissue defects were repaired using radial forearm (n = 22) or rectus abdominis (n= 5) free flaps. MAIN OUTCOME MEASURE: Incidence of hardware-related complications. RESULTS: All microvascular flap transfers were successful. One patient experienced a plate fracture 9 months after reconstruction. Only 1 patient experienced external plate exposure, 6 months after undergoing reconstruction of a through-and-through defect. Reconstruction was successful in 25 (93%) of the cases after a median follow-up period of 19.5 months. CONCLUSIONS: The high incidence of external plate exposure in patients undergoing lateral oromandibular reconstruction using soft tissue free flaps and first-generation locking MRPs may have resulted from a plate geometry that was prone to result in extrusion. After a similar length of follow-up, the incidence of reconstructive failure was reduced by using a low-profile, rounded-contour MRP. Final assessment of the durability of this technique will require long-term follow-up.

An equine protozoal myeloencephalitis challenge model testing a second transport after inoculation with Sarcocystis neurona sporocysts.

Previous challenge studies performed at Ohio State University involved a transport-stress model where the study animals were dosed with Sarcocystis neurona sporocysts on the day of arrival. This study was to test a second transportation of horses after oral inoculation with S. neurona sporocysts. Horses were assigned randomly to groups: group 1, transported 4 days after inoculation (DAI); group 2, at 11 DAI; group 3, at 18 DAI; and group 4, horses were not transported a second time (controls). An overall neurologic score was determined on the basis of a standard numbering system used by veterinarians. All scores are out of 5, which is the most severely affected animal. The mean score for the group 1 horses was 2.42; group 2 horses was 2.5; group 3 horses was 2.75; and group 4 horses was 3.25. Because the group 4 horses did not have a second transport, they were compared with all other groups. Statistically different scores were present between group 4 and groups 1 and 2. There was no difference in the time of seroconversion between groups. There was a difference between the time of onset of first clinical signs between groups 1 and 4. This difference was likely because of the different examination days. Differences in housing and handling were likely the reason for the differences in severity of clinical signs. This model results in consistent, significant clinical signs in all horses at approximately the same time period after inoculation but was most severe in horses that did not experience a second transport.

Radial forearm free flap for soft palate reconstruction.

Defects of the soft palate resulting from head and neck oncologic surgery traditionally have been rehabilitated using a prosthetic obturator. In general, the results of soft palate obturation have been satisfactory, with most patients achieving velopharyngeal competence during speech and swallowing. However, soft palate obturators have several disadvantages. Device stability and retention are impaired in patients who are edentulous. In addition, prosthetic obturators cover large areas of sensate mucosa in the hard palate, maxillary alveolus, and oropharynx, contributing significantly to the loss of sensory feedback from the oral cavity and oropharynx. Considerable evidence suggests that sensory impairment within the oral cavity and pharynx results in impaired mastication, deglutition, and articulation. A minority of patients find palatal obturators to be unsatisfactory, secondary to either inconvenience or device discomfort.

Autologous fibroblasts for treatment of facial rhytids and dermal depressions. A pilot study.

OBJECTIVE: To assess effectiveness of intradermal injections of autologous fibroblasts for the treatment of facial rhytids and dermal depressions. DESIGN: Six-month prospective pilot study. Photographs and silicone molds were taken of a prominent rhytid or dermal depression from each patient prior to treatment and at 6 months after treatment. SETTING: Specialty clinic in academic medical center. PATIENTS: Ten adults (age range, 24-69 years) who each exhibited a prominent rhytid or depressed facial scar. INTERVENTION: A 3-mm postauricular skin biopsy specimen from each participant was sent to Isolagen Technologies, Inc, laboratories, where a fibroblast cell line was developed. Three injection sessions were performed at 2-week intervals; target areas were the study site as well as behind the ear. MAIN OUTCOME MEASURES: Subjective improvement scores were obtained by each patient and 2 clinicians at every follow-up visit. Skin surface topographical features were evaluated with optical profilometry by comparing silicone molds before and after injection. Histological analysis was performed on a biopsy specimen of the postauricular injection site. RESULTS: Nine of 10 patients noted a 60% to 100% improvement with the treatment; clinicians made similar observations. Size reduction of 10% up to 85% of the study site was demonstrated by optical profilometry for every patient. Microscopically, there was evidence of increased thickness and density of dermal-layer collagen. CONCLUSIONS: Intradermal injection of autologous fibroblasts may be an effective treatment option for facial rhytids and depressed scars.

High intensity exercise conditioning increases accumulated oxygen deficit of horses.

High intensity exercise is associated with production of energy by both aerobic and anaerobic metabolism. Conditioning by repeated exercise increases the maximal rate of aerobic metabolism, aerobic capacity, of horses, but whether the maximal amount of energy provided by anaerobic metabolism, anaerobic capacity, can be increased by conditioning of horses is unknown. We, therefore, examined the effects of 10 weeks of regular (4-5 days/week) high intensity (92+/-3 % VO2max) exercise on accumulated oxygen deficit of 8 Standardbred horses that had been confined to box stalls for 12 weeks. Exercise conditioning resulted in increases of 17% in VO2max (P<0.001), 11% in the speed at which VO2max was achieved (P = 0.019) and 9% in the speed at 115% of VO2max (P = 0.003). During a high speed exercise test at 115% VO2max, sprint duration was 25% longer (P = 0.047), oxygen demand was 36% greater (P<0.001), oxygen consumption was 38% greater (P<0.001) and accumulated oxygen deficit was 27% higher (P = 0.040) than values before conditioning. VLa4 was 33% higher (P<0.05) after conditioning. There was no effect of conditioning on blood lactate concentration at the speed producing VO2max or at the end of the high speed exercise test. The rate of increase in muscle lactate concentration was greater (P = 0.006) in horses before conditioning. Muscle glycogen concentrations before exercise were 17% higher (P<0.05) after conditioning. Exercise resulted in nearly identical (P = 0.938) reductions in muscle glycogen concentrations before and after conditioning. There was no detectable effect of conditioning on muscle buffering capacity. These results are consistent with a conditioning-induced increase in both aerobic and anaerobic capacity of horses demonstrating that anaerobic capacity of horses can be increased by an appropriate conditioning programme that includes regular, high intensity exercise. Furthermore, increases in anaerobic capacity are not reflected in blood lactate concentrations measured during intense, exhaustive exercise or during recovery from such exercise.

Diagnostic validity of electroencephalography in equine intracranial disorders.

Electroencephalography (EEG) is a valuable diagnostic test to identify functional disturbances in brain activity. The purpose of this study was to assess the validity of EEG as a diagnostic indicator of intracranial diseases in horses. The validity of EEG was estimated by comparing clinical, clinicopathologic, and histopathologic findings to EEG findings in 20 horses examined for seizures. collapse, or abnormal behavior between 1984 and 1997. A bipolar left-to-right, back-to-front montage and a bipolar circular montage were recorded from sedated (4) and anesthetized (16) horses. Visual and semiquantitative masked analysis of EEG recording Ist was validated on 10 horses presented for problems other than intracranial diseases. EEG pattern was normal in 7 of the 20 clinically affected horses. Abnormal EEG patterns included high-voltage slow waves and discrete paroxysmal activity with or without generalized activity in 13 horses. Histopathologic diagnoses in 10 horses included meningoencephalitis, neuronal necrosis, congenital anomalies. cerebral edema. and abscess. All of these horses had abnormal EEG patterns (sensitivity, 100%) with a positive neuroanatomic correlation in 7 animals. Localization of histopathologic and EEG abnormalities did not correlate in 15% of the horses (3/20). The cause of neurologic signs could not be explained at postmortem examination in 10 animals and the EEG pattern was normal in 7 of these horses (specificity, 70%). In conclusion, equine EEG was a sensitive tool in the diagnosis of intracranial disorders.

Distribution and predictive factors of seizure types in 104 cases.

REASONS FOR PERFORMING THE STUDY: Although many studies have been performed to classify seizures by type in man and small animals, a similar study in horses is lacking. OBJECTIVES: The aims of this study were as follows: 1) to characterise the distribution of seizure types in 104 horses presented for seizure disorders to a referral veterinary hospital; and 2) to characterise the various types of seizures by identifying associated clinical factors. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Seizures were classified based on seizure type, according to the most recent accepted definitions in both human and small animal epileptology. History, clinical and neurological examinations, diagnostic investigations and post mortem examinations, when available, were recorded for univariable and multivariable logistic regression analyses. RESULTS: Seizures were categorised as primary generalised in 23% of horses, focal without secondary generalisation in 42% of cases and secondary generalised in 24% of cases. The type of seizure could not be classified in 11% of cases. Significant associations were found between seizure type and the following characteristics: 1) gender; 2) frequency of seizures; and 3) presence of seizures during hospitalisation. Seizure type was not significantly associated with aetiology. For a horse with recurrent seizures, the odds of having focal seizures was 3.7 times higher (P = 0.02) than in a similar horse with nonrecurring seizures in the final logistic regression model. CONCLUSIONS: The majority of the seizures described were focal seizures with or without secondary generalisation. The clinical presentation was independent of the underlying disease.

Toll-like receptor and pro-inflammatory cytokine expression during prolonged hyperinsulinaemia in horses: implications for laminitis.

Equine laminitis, a disease of the lamellar structure of the horse's hoof, can be incited by numerous factors that include inflammatory and metabolic aetiologies. However, the role of inflammation in hyperinsulinaemic laminitis has not been adequately defined. Toll-like receptor (TLR) activation results in up-regulation of inflammatory pathways and the release of pro-inflammatory cytokines, including interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), and may be a pathogenic factor in laminitis. The aim of this study was to determine whether TLR4 expression and subsequent pro-inflammatory cytokine production is increased in lamellae and skeletal muscle during equine hyperinsulinaemia. Standardbred horses were treated with either a prolonged, euglycaemic hyperinsulinaemic clamp (p-EHC) or a prolonged, glucose infusion (p-GI), which induced marked and moderate hyperinsulinaemia, respectively. Age-matched control horses were treated simultaneously with a balanced electrolyte solution. Treated horses developed clinical (p-EHC) or subclinical (p-GI) laminitis, whereas controls did not. Skeletal muscle and lamellar protein extracts were analysed by Western blotting for TLR4, IL-6, TNF-α and suppressor of cytokine signalling 3 (SOCS3) expression. Lamellar protein expression of TLR4 and TNF-α, but not IL-6, was increased by the p-EHC, compared to control horses. A significant positive correlation was found between lamellar TLR4 and SOCS3. Skeletal muscle protein expression of TLR4 signalling parameters did not differ between control and p-EHC-treated horses. Similarly, the p-GI did not result in up-regulation of lamellar protein expression of any parameter. The results suggest that insulin-sensitive tissues may not accurately reflect lamellar pathology during hyperinsulinaemia. While TLR4 is present in the lamellae, its activation appears unlikely to contribute significantly to the developmental pathogenesis of hyperinsulinaemic laminitis. However, inflammation may have a role to play in the later stages (e.g., repair or remodelling) of the disease.

Novel link between inflammation and impaired glucose transport during equine insulin resistance.

Although insulin resistance (IR) has been increasingly recognized in horses, a clear understanding of its pathophysiology is lacking. The purpose of the present study was to determine the early pathologic changes in IR horses by characterizing alterations in proteins that play key roles in innate immunological responses and inflammatory pathways, and by identifying potential links with glucose transport and insulin signaling. Visceral (VIS) and subcutaneous (SC) adipose tissue and skeletal muscle (SM) biopsies were collected from horses, which were classified as insulin-sensitive (IS) or IR based on the results of an insulin-modified frequently sampled intravenous glucose tolerance test. Protein expression of Toll-like receptor 4 (TLR-4), suppressor of cytokine signaling 3 (SOCS-3) and tumor necrosis factor alpha (TNF-α) were quantified by Western blotting in VIS and SC adipose depots and SM, as well as insulin receptor substrate 1 (IRS-1). To better characterize the potential relationship between inflammation, IR and impaired glucose transport, we correlated active cell surface glucose transporter 4 (GLUT-4) content (measured by a cell surface biotinylated assay) with individual- and tissue-specific data related to inflammation. IR was associated with a significantly increased expression of TLR-4 and SOCS-3 in SM and VIS tissue, without a significant change in SC site. We also observed a significant increase in TNF-α in VIS, but not in SC, tissue of IR vs. IS horses. There was no difference in total content or serine phosphorylation of IRS-1 for any sampling site in IR compared to IS horses. We further observed a significant positive correlation between TLR-4 content and SOCS-3, as well as a significant negative correlation between SOCS-3 content and GLUT-4 trafficking. Taken together, the data suggested a pro-inflammatory state in SM and VIS, but not SC, adipose depot during compensated IR. In addition, SOCS-3 appears to be a novel link between inflammation and dysregulated glucose metabolism and insulin sensitivity during the early pathogenesis of insulin resistance.

Epilepsy in horses: aetiological classification and predictive factors.

REASONS FOR PERFORMING THE STUDY: In contrast with reports in man and small animals, a systematic classification of seizures in horses is lacking. OBJECTIVES: The purpose of this study was to classify seizures based on their aetiology and to characterise epilepsy in 104 horses presented for seizures at the Ohio State University Veterinary Medical Center between 1988 and 2009. METHODS: In a retrospective observational study, seizures were classified by aetiology based on history, clinical observations, diagnostic investigations (e.g. electroencephalograms, cerebrospinal fluid and computed tomography imaging of the head) and post mortem examinations, when available. Univariate and multivariate logistic regression analyses were performed. RESULTS: Epilepsy (i.e. 2 or more recurrent seizures) was identified in 70% of cases, and further classified as symptomatic (i.e. structural brain pathology, 35.6% of cases), cryptogenic (i.e. unknown, 54.8% of cases) and idiopathic (i.e. suspected genetic predisposition, 2.7% of cases). Normal neurological examination on admission, the presence of seizures unprovoked by any identified factors and paroxysmal epileptiform activity on electroencephalogram recordings were all strongly (P<0.05) correlated with epilepsy on univariate analysis. For a horse with generalised seizures, the odds of having epilepsy was 7 times lower compared with a similar horse with partial seizures (P<0.05) in multivariate modelling. CONCLUSIONS: Seizure aetiology was symptomatic or cryptogenic in most horses, whereas reactive seizures and idiopathic epilepsy were less common. POTENTIAL RELEVANCE: This study is the first attempt to classify seizures and to characterise epilepsy in a referral-based equine population. Predictive factors of epilepsy in horses were similar to those reported in other species and may assist the clinician with the early diagnosis of epilepsy.