In Silico Human Cardiomyocyte Action Potential Modeling: Exploring Ion Channel Input Combinations.

In silico modeling offers an opportunity to supplement and accelerate cardiac safety testing. With in silico modeling, computational simulation methods are used to predict electrophysiological interactions and pharmacological effects of novel drugs on critical physiological processes. The O'Hara-Rudy's model was developed to predict the response to different ion channel inhibition levels on cardiac action potential duration (APD) which is known to directly correlate with the QT interval. APD data at 30% 60% and 90% inhibition were derived from the model to delineate possible ventricular arrhythmia scenarios and the marginal contribution of each ion channel to the model. Action potential values were calculated for epicardial, myocardial, and endocardial cells, with action potential curve modeling. This study assessed cardiac ion channel inhibition data combinations to consider when undertaking in silico modeling of proarrhythmic effects as stipulated in the Comprehensive in Vitro Proarrhythmia Assay (CiPA). As expected, our data highlight the importance of the delayed rectifier potassium channel (IKr) as the most impactful channel for APD prolongation. The impact of the transient outward potassium channel (Ito) inhibition on APD was minimal while the inward rectifier (IK1) and slow component of the delayed rectifier potassium channel (IKs) also had limited APD effects. In contrast, the contribution of fast sodium channel (INa) and/or L-type calcium channel (ICa) inhibition resulted in substantial APD alterations supporting the pharmacological relevance of in silico modeling using input from a limited number of cardiac ion channels including IKr, INa, and ICa, at least at an early stage of drug development.

Concurrent Validation of MI-CAT(V), a Clinical Metrology Instrument for Veterinarians Assessing Osteoarthritis Pain in Cats, through Testing for Firocoxib Analgesic Efficacy in a Prospective, Randomized, Controlled, and Blinded Study.

Veterinarians face the lack of a rapid, reliable, inexpensive, and treatment-sensitive metrological instrument reflecting feline osteoarthritis (OA) pain. The Montreal Instrument for Cat Arthritis Testing, for Use by Veterinarians (MI-CAT(V)) has been refined in 4 sub-sections, and we proposed its concurrent validation. Cats naturally affected by OA (n = 32) were randomly distributed into 4 groups of firocoxib analgesic (Gr. A: 0.40; B: 0.25; C: 0.15, and P: 0.00 mg/kg bodyweight). They were assessed during Baseline, Treatment, and Recovery periods using MI-CAT(V) and objective outcomes (effort path, stairs assay compliance, and actimetry). The MI-CAT(V) total score correlated to the effort path and actimetry (RhoS = -0.501 to -0.453; p < 0.001), also being sensitive to treatment responsiveness. The pooled treatment group improved its total, gait, and body posture scores during Treatment compared to the Baseline, Recovery, and placebo group (p < 0.05). The MI-CAT(V) suggested a dose-(especially for Gr. B) and cluster-response. Cats in the moderate and severe MI-CAT(V) clusters responded to firocoxib with a remaining analgesic effect, while the mild cluster seemed less responsive and experienced a negative rebound effect. The MI-CAT(V) was validated for its OA pain severity discriminatory abilities and sensitivity to firocoxib treatment, providing a new perspective for individualized care.

Comparison of intradermal and serum testing for environmental allergen-specific immunoglobulin E determination in a laboratory colony of cats with naturally acquired atopic syndrome.

BACKGROUND: Allergen testing is used to select antigens included in the desensitisation vaccine. Intradermal skin test (IDT) is the gold standard in cats, yet allergen-specific immunoglobulin (Ig)E serological testing (ASIS) is often used. Feline data are lacking regarding the agreement between IDT and ASIS results. HYPOTHESIS/OBJECTIVES: The first objective of the study was to establish a colony of cats with naturally acquired feline atopic syndrome (FAS). Further objectives were to define their hypersensitivity disorder to detail the allergen tests results, and to assess similarity between the allergen tests. ANIMALS: Thirty-five cats with FAS and 10 control cats. MATERIALS AND METHODS: Enrolled cats went through a five phase-screening and quarantine process before joining the colony. An elimination diet trial was performed on all FAS cats. ASIS and IDT were consecutively performed on all cats under sedation. RESULTS: Reactions to 34 allergens were compiled for the 45 cats. Global sensitivity and specificity of ASIS were 34.7% and 78.9%, respectively. Only flea (ICC = 0.26, p = 0.040) and Dermatophagoides pteronyssinus (ICC = 0.48, p < 0.001) allergens had a significant intraclass correlation (weak agreement). Two FAS cats had negative tests including one cat with a concomitant food allergy. CONCLUSIONS AND CLINICAL RELEVANCE: This study depicts the first reported colony of cats with naturally acquired FAS. This is the first feline study to compare and show the poor agreement between allergen tests with a panel of 34 allergens. This colony also harbours two cats with FAS with negative allergen tests. These may represent the first described cats with an intrinsic form of atopic syndrome.

The Spontaneous Incidence of Neurological Clinical Signs in Preclinical Species Using Cage-side Observations or High-definition Video Monitoring: A Retrospective Analysis.

When conducting toxicology studies, the interpretation of drug-related neurological clinical signs such as convulsions, myoclonus/myoclonic jerks, tremors, ataxia, and salivation requires an understanding of the spontaneous incidence of those observations in commonly used laboratory animal species. The spontaneous incidence of central nervous system clinical signs in control animals from a single facility using cage-side observations or high definition video monitoring was retrospectively analyzed. Spontaneous convulsions were observed at low incidence in Beagle dogs and Sprague-Dawley rats but were not identified in cynomolgus monkeys and Göttingen minipigs. Spontaneous myoclonic jerks and muscle twitches were observed at low incidence in Beagle dogs, cynomolgus monkeys, and Sprague-Dawley rats but were not seen in Göttingen minipigs. Spontaneous ataxia/incoordination was identified in all species and generally with a higher incidence when using video monitoring. Salivation and tremors were the two most frequent spontaneous clinical signs and both were observed in all species. Data from the current study unveil potential limitations when using control data obtained from a single study for toxicology interpretation related to low incidence neurological clinical signs while providing historical control data from Beagle dogs, cynomolgus monkeys, Sprague-Dawley rats, and Göttingen minipigs.

Face and Predictive Validity of MI-RAT (Montreal Induction of Rat Arthritis Testing), a Surgical Model of Osteoarthritis Pain in Rodents Combined with Calibrated Exercise.

Validating animal pain models is crucial to enhancing translational research and response to pharmacological treatment. This study investigated the effects of a calibrated slight exercise protocol alone or combined with multimodal analgesia on sensory sensitivity, neuroproteomics, and joint structural components in the MI-RAT model. Joint instability was induced surgically on day (D) 0 in female rats (N = 48) distributed into sedentary-placebo, exercise-placebo, sedentary-positive analgesic (PA), and exercise-PA groups. Daily analgesic treatment (D3-D56) included pregabalin and carprofen. Quantitative sensory testing was achieved temporally (D-1, D7, D21, D56), while cartilage alteration (modified Mankin's score (mMs)) and targeted spinal pain neuropeptide were quantified upon sacrifice. Compared with the sedentary-placebo (presenting allodynia from D7), the exercise-placebo group showed an increase in sensitivity threshold (p < 0.04 on D7, D21, and D56). PA treatment was efficient on D56 (p = 0.001) and presented a synergic anti-allodynic effect with exercise from D21 to D56 (p < 0.0001). Histological assessment demonstrated a detrimental influence of exercise (mMs = 33.3%) compared with sedentary counterparts (mMs = 12.0%; p < 0.001), with more mature transformations. Spinal neuropeptide concentration was correlated with sensory sensitization and modulation sites (inflammation and endogenous inhibitory control) of the forced mobility effect. The surgical MI-RAT OA model coupled with calibrated slight exercise demonstrated face and predictive validity, an assurance of higher clinical translatability.

Modulating the activity of human nociceptors with a SCN10A promoter-specific viral vector tool.

Despite the high prevalence of chronic pain as a disease in our society, there is a lack of effective treatment options for patients living with this condition. Gene therapies using recombinant AAVs are a direct method to selectively express genes of interest in target cells with the potential of, in the case of nociceptors, reducing neuronal firing in pain conditions. We designed a recombinant AAV vector expressing cargos whose expression was driven by a portion of the SCN10A (NaV1.8) promoter, which is predominantly active in nociceptors. We validated its specificity for nociceptors in mouse and human dorsal root ganglia and showed that it can drive the expression of functional proteins. Our viral vector and promoter package drove the expression of both excitatory or inhibitory DREADDs in primary human DRG cultures and in whole cell electrophysiology experiments, increased or decreased neuronal firing, respectively. Taken together, we present a novel viral tool that drives expression of cargo specifically in human nociceptors. This will allow for future specific studies of human nociceptor properties as well as pave the way for potential future gene therapies for chronic pain.

Development of Two Innovative Performance-Based Objective Measures in Feline Osteoarthritis: Their Reliability and Responsiveness to Firocoxib Analgesic Treatment.

The metrological properties of two performance-based outcome measures of feline osteoarthritis (OA), namely Effort Path (Path) and Stairs Assay Compliance (Stairs), were tested. Cats naturally affected by OA (n = 32) were randomly distributed into four groups (A: 0.40, B: 0.25, C: 0.15, or D: 0.00 mg firocoxib/kg bodyweight) and assessed during baseline, treatment, and recovery periods. For Path, from an elevated walking platform, the cats landed on a pressure-sensitive mattress and jumped up onto a second elevated platform. Analysis included velocity, time to completion, peak vertical force (PVF), and vertical impulse. For Stairs, the number of steps and time to completion were recorded for 16 steps up and down in a 4 min period. Reliability was moderate to very good for Path and poor to good for Stairs. Different normalization methods are described in the manuscript. The placebo group remained stable within-time in Path, whereas treated cats trotted faster on the ramp (p < 0.0001), improved their PVF (p < 0.018) and completed the task quicker (p = 0.003). The percentage of cats completing the Stairs finish line was higher under treatment (p < 0.036), with huge effect size, the placebo group results being stable within-time. Both are promising performance-based outcome measures to better diagnose and manage feline OA pain.

A 2022 Systematic Review and Meta-Analysis of Enriched Therapeutic Diets and Nutraceuticals in Canine and Feline Osteoarthritis.

With osteoarthritis being the most common degenerative disease in pet animals, a very broad panel of natural health products is available on the market for its management. The aim of this systematic review and meta-analysis, registered on PROSPERO (CRD42021279368), was to test for the evidence of clinical analgesia efficacy of fortified foods and nutraceuticals administered in dogs and cats affected by osteoarthritis. In four electronic bibliographic databases, 1578 publications were retrieved plus 20 additional publications from internal sources. Fifty-seven articles were included, comprising 72 trials divided into nine different categories of natural health compound. The efficacy assessment, associated to the level of quality of each trial, presented an evident clinical analgesic efficacy for omega-3-enriched diets, omega-3 supplements and cannabidiol (to a lesser degree). Our analyses showed a weak efficacy of collagen and a very marked non-effect of chondroitin-glucosamine nutraceuticals, which leads us to recommend that the latter products should no longer be recommended for pain management in canine and feline osteoarthritis.

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1-4.

The Canadian consensus guidelines on OA treatment were created from a diverse group of experts, with a strong clinical and/or academic background in treating OA in dogs. The document is a summary of the treatment recommendations made by the group, with treatments being divided into either a core or secondary recommendation. Each treatment or modality is then summarized in the context of available research based support and clinical experience, as the treatment of OA continues to be a multimodal and commonly a multidisciplinary as well as individualized approach. The guidelines aim to help clinicians by providing clear and clinically relevant information about treatment options based on COAST defined OA stages 1-4.

Estrogenic impregnation alters pain expression: analysis through functional neuropeptidomics in a surgical rat model of osteoarthritis.

PURPOSE: Several observational studies suggest that estrogens could bias pain perception. To evaluate the influence of estrogenic impregnation on pain expression, a prospective, randomized, controlled, blinded study was conducted in a Sprague-Dawley rat model of surgically induced osteoarthritis (OA). METHODS: Female rats were ovariectomized and pre-emptive 17ß-estradiol (0.025 mg, 90-day release time) or placebo pellets were installed subcutaneously during the OVX procedures. Thirty-five days after, OA was surgically induced on both 17ß-estradiol (OA-E) and placebo (OA-P) groups. Mechanical hypersensitivity was assessed by static weight-bearing (SWB) and paw withdrawal threshold (PWT) tests. Mass spectrometry coupled with high-performance liquid chromatography (HPLC-MS) was performed to quantify the spinal pronociceptive neuropeptides substance P (SP), calcitonin gene-related peptide (CGRP), bradykinin (BK), somatostatin (SST), and dynorphin-A (Dyn-A). RESULTS: Compared to control, ovariectomized rats presented higher SP (P = 0.009) and CGRP (P = 0.017) concentrations. OA induction increased the spinal level of SP (+ 33%, P < 0.020) and decreased the release of BK (- 20%, (P < 0.037)). The OA-E rats at functional assessment put more % body weight on the affected hind limb than OA-P rats at D7 (P = 0.027) and D56 (P = 0.033), and showed higher PWT at D56 (P = 0.009), suggesting an analgesic and anti-allodynic effect of 17ß-estradiol. Interestingly, the 17ß-estradiol treatment counteracted the increase of spinal concentration of Dyn-A (P < 0.016) and CGRP (P < 0.018). CONCLUSION: These results clearly indicate that 17ß-estradiol interfers with the development of central sensitization and confirm that gender dimorphism should be considered when looking at pain evaluation.

Combined Cardiopulmonary Assessments Using Impedance and Digital Implants in Conscious Freely Moving Cynomolgus Monkeys, Beagle Dogs, and Göttingen Minipigs: Pharmacological Characterization and Social Housing Effects.

Respiratory monitoring, using impedance with implanted telemetry in socially housed animals, was not possible until the recent development of digital signal transmission. The objective of this study was to evaluate digital telemetry monitoring of cardiopulmonary parameters (respiratory rate, tidal volume, minute volume, electrocardiography (DII), systemic arterial blood pressure, physical activity, and body temperature) in conscious, single-housed, non-rodent species commonly used in toxicology studies following administration of positive/negative controls (saline, dexmedetomidine, morphine, amphetamine, and doxapram), and also, the effects of various social housing arrangements in untreated female and/or male cynomolgus monkeys, Beagle dogs, and Göttingen minipigs (n = 4 per species). Aggressions were observed in socially housed male minipigs, however, which prevented pair-housed assessments in this species. All tested pharmacological agents significantly altered more than one organ system, highlighting important inter-organ dependencies when analyzing functional endpoints. Stress-related physiological changes were observed with single-housing or pair-housing with a new cage mate in cynomolgus monkeys and Beagle dogs, suggesting that stable social structures are preferable to limit variability, especially around dosing. Concomitant monitoring of cardiovascular and respiratory parameters from the same animals may help reduce the number of animals (3 Rs) needed to fulfill the S7A guidelines and allows for identification of organ system functional correlations. Globally, the data support the use of social housing in non-rodents for safety pharmacology multi-organ system (heart and lungs) monitoring investigations.

Management of veterinary anaesthesia and analgesia in small animals: A survey of English-speaking practitioners in Canada.

OBJECTIVE: To describe how small animal anaesthesia and analgesia is performed in English-speaking Canada, document any variation among practices especially in relation to practice type and veterinarian's experience and compare results to published guidelines. DESIGN: Observational study, electronic survey. SAMPLE: 126 respondents. PROCEDURE: A questionnaire was designed to assess current small animal anaesthesia and analgesia practices in English-speaking Canadian provinces, mainly in Ontario, Alberta and British Columbia. The questionnaire was available through SurveyMonkey® and included four parts: demographic information about the veterinarians surveyed, evaluation and management of anaesthetic risk, anaesthesia procedure, monitoring and safety. Year of graduation and type of practice were evaluated as potential risk factors. Exact chi-square tests were used to study the association between risk factors and the association between risk factors and survey responses. For ordinal data, the Mantel-Haenszel test was used instead. RESULTS: Response rate over a period of 3 months was 12.4% (126 respondents out of 1 016 invitations). Current anaesthesia and analgesia management failed to meet international guidelines for a sizable number of participants, notably regarding patient evaluation and preparation, safety and monitoring. Nearly one third of the participants still consider analgesia as optional for routine surgeries. Referral centres tend to follow guidelines more accurately and are better equipped than general practices. CONCLUSIONS AND CLINICAL RELEVANCE: A proportion of surveyed Canadian English-speaking general practitioners do not follow current small animal anaesthesia and analgesia guidelines, but practitioners working in referral centres are closer to meet these recommendations.

Confounders and Pharmacological Characterization When Using the QT, JTp, and Tpe Intervals in Beagle Dogs.

INTRODUCTION: Corrected QT (QTc) interval is an essential proarrhythmic risk biomarker, but recent data have identified limitations to its use. The J to T-peak (JTp) interval is an alternative biomarker for evaluating drug-induced proarrhythmic risk. The aim of this study was to evaluate pharmacological effects using spatial magnitude leads and DII electrocardiogram (ECG) leads and common ECG confounders (ie, stress and body temperature changes) on covariate adjusted QT (QTca), covariate adjusted JTp (JTpca), and covariate adjusted T-peak to T-end (Tpeca) intervals. METHODS: Beagle dogs were exposed to body hyper- (42 °C) or hypothermic (33 °C) conditions or were administered epinephrine to assess confounding effects on heart rate corrected QTca, JTpca, and Tpeca intervals. Dofetilide (0.1, 0.3, 1.0 mg/kg), ranolazine (100, 140, 200 mg/kg), and verapamil (7, 15, 30, 43, 62.5 mg/kg) were administered to evaluate pharmacological effects. RESULTS: Covariate adjusted QT (slope -12.57 ms/°C) and JTpca (-14.79 ms/°C) were negatively correlated with body temperature but Tpeca was minimally affected. Epinephrine was associated with QTca and JTpca shortening, which could be related to undercorrection in the presence of tachycardia, while minimal effects were observed for Tpeca. There were no significant ECG change following ranolazine administration. Verapamil decreased QTca and JTpca intervals and increased Tpeca, whereas dofetilide increased QTca and JTpca intervals but had inconsistent effects on Tpeca. CONCLUSION: Results highlight potential confounders on QTc interval, but also on JTpca and Tpeca intervals in nonclinical studies. These potential confounding effects may be relevant to the interpretation of ECG data obtained from nonclinical drug safety studies with Beagle dogs.

Management of veterinary anaesthesia in small animals: A survey of current practice in Quebec.

OBJECTIVE: To describe how small animal anaesthesia is performed in French-speaking Eastern Canada, and the variations between practices, in particular based on practice type, veterinarian gender and experience. DESIGN: Observational study, survey. SAMPLE: 156 respondents. PROCEDURE: A questionnaire was designed to assess current small animal anaesthesia practices in French-speaking Eastern Canada, mainly in the province of Quebec. The questionnaire was available through SurveyMonkey, and consisted of four parts: demographic information about the veterinarians surveyed, evaluation and management of anaesthetic risk, anaesthesia procedure, monitoring and safety. Gender, year of graduation, and type of practice were tested as potential risk factors. Chi-square exact test was used to study relations between each risk factor, and the effect of the selected risk factor on each response of the survey. For ordinal data, the Cochran-Mantel-Haenszel test was used to maximize power. RESULTS: Response rate over a period of 3 months was 20.85% (156 respondents). Overall, the way anaesthesia is performed by most respondents does not meet international guidelines, such as patient preparation and evaluation prior to anaesthesia, not using individualised protocols (for 41%), not obtaining intravenous access (12.4% use it for all their anaesthesia in cats, and 30.6% in dogs), lack of patient monitoring at certain intervals for 55% of the responses, and client prompted optional analgesia (for 29% of respondents). Some practices are more compliant than others. Among them, referral centres generally offer better care than general practices. CONCLUSIONS AND CLINICAL RELEVANCE: The level of care in anaesthesia and analgesia in practices in French-speaking Eastern Canada is concerning, highlighting the need for more sustained continuing education.

Reprint of "EEG: Characteristics of drug-induced seizures in rats, dogs and non-human primates".

Seizures are amongst the most frequent neurological issues encountered in pre-clinical safety testing. The objective was to characterize EEG morphologies and premonitory signs in drug-induced seizures in preclinical species. A comparative (inter-species) retrospective analysis for drug-induced seizures recorded by video-telemetry was conducted in rats (n = 53), dogs (n = 195), and non-human primates (n = 234). The most frequent premonitory signs were, in rats, myoclonus (100%), tremors (93%), salivation (75%), partial ptosis (58%) and chewing/bruxism (58%); in dogs, tremors (77%), ataxia/uncoordination (60%), myoclonus (45%), salivation (43%), excessive licking (38%), high vocalization (38%) and decreased activity (34%); in non-human primates, tremors (79%), decreased activity (70%), myoclonus (57%), retching/emesis (37%), hunched posture (30%) and ataxia/uncoordination (27%). Seizure duration ranged from 3 s to 14 min with an average of 46 ±â€¯21 s, comparable across species. At seizure onset, spike frequency averaged 9.4 Hz for the three species compared to 4.3 Hz at seizure end. Peak average amplitudes were attained at mid-seizure and amplitudes at seizure end decreased from peak but remained higher than onset amplitudes. Spike duration was inversely correlated with frequency and presented a crescendo pattern. Morphological characteristics can serve to refine automated EEG analysis. From a regulatory perspective, the most common paradigm is to use the most sensitive species in seizure liability studies but translational potential and clinical relevance may be under represented in the decision making process in some cases. EEG morphologies during drug-induced seizures presented remarkable similarities between species and tremors were identified as a predominant premonitory clinical sign in all species.

Safety and efficacy of reduced dosage ketoprofen with or without tramadol for long-term treatment of osteoarthritis in dogs: a randomized clinical trial.

BACKGROUND: This study aimed to evaluate the safety and efficacy of reduced-dosage ketoprofen with or without tramadol in dogs. Five healthy dogs receiving standard-dosage ketoprofen (2 mg/kg SC, then 1 mg/kg PO daily) comprised Group A. Twenty dogs with osteoarthritis were randomized to receive reduced-dosage ketoprofen (0.5 mg/kg SC once; 0.25 mg/kg PO daily) alone (Group B) or in combination with tramadol (5 mg/kg/day PO) (Group C). Treatments were administered for 28 days. Platelet aggregation time (PAT), gastrointestinal (GI) endoscopy and glomerular filtration rate (GFR) were performed up to 60 days after treatment initiation. Pain was scored using a validated clinical metrology instrument up to D120. Data were analyzed with general linear mixed model for repeated measures (α = 0.05). RESULTS: PAT was not different between groups but was increased with time for all groups. GI lesion scores were higher in Group A than Groups B and C (day 28; P = 0.005) and were increased with time for Group A (P = 0.005). GFR was lower in Group A than Groups B and C (day 28; P < 0.01) and were decreased with time for group A (P < 0.001). Standard-dosage ketoprofen administration resulted in clinically relevant adverse effects. Pain score decreased in both treated groups (B and C) from D0 to D28. Need of rescue analgesia from D29 to D120 was higher in Group B than in Group C (P = 0.039). CONCLUSIONS: The long-term safety profile of reduced-dosage ketoprofen is similar whether the drug is administered alone or in combination with tramadol to dogs with osteoarthritis. Analgesic efficacy of the combination looks attractive.

Incidence of spontaneous arrhythmias in freely moving healthy untreated Sprague-Dawley rats.

Spontaneous arrhythmia characterization in healthy rats can support interpretation when studying novel therapies. Male (n = 55) and female (n = 40) Sprague-Dawley rats with telemetry transmitters for a derivation II ECG. Arrhythmias were assessed from continuous ECG monitoring over a period of 24-48 h, and data analyzed using an automated detection algorithm with 100% manual over-read. While a total of 1825 spontaneous ventricular premature beats (VPB) were identified, only 7 rats (or 7.4%) did not present with any over the recording period. Spontaneous episode(s) of ventricular tachycardia (VT) were noted in males (27%) and females (3%). The incidence of VPB was significantly higher (p < 0.01) during the night time (7 pm-7 am) compared to daytime, while males presented with significantly (p < 0.001) more VPB than females. Most VPB were observed as single ectopic beats, followed by salvos (2 or 3 consecutive VPBs), and VT (i.e. 4 consecutive VPBs). Most VPBs were single premature ventricular contractions (PVCs) (57%), while the remaining were escape complexes (43%). Spontaneous premature junctional complexes (PJC) were also observed and were significantly more frequent during the night, and in males. Lastly, 596 episodes of spontaneous 2nd-degree atrioventricular (AV) block were identified and were significantly more frequent during the day time in males. Most 2nd-degree AV block episodes were Mobitz type I (57%), with a significantly (p < 0.05) higher incidence in males. This work emphasizes the importance of obtaining sufficient baseline data when undertaking arrhythmia analysis in safety study and provides a better understanding of both sex- and time- dependent effects of spontaneous arrhythmias in rats.

Sensitivity of functional targeted neuropeptide evaluation in testing pregabalin analgesic efficacy in a rat model of osteoarthritis pain.

The monosodium iodoacetate (MIA)-induced joint degeneration in rats is the most used animal model to screen analgesic drugs to alleviate osteoarthritis (OA) pain. This study aimed to evaluate the analgesic efficacy of pregabalin (PGB) in an MIA-induced OA model in rodents by using functional and neuroproteomic pain assessment methods. Treatment group included PGB in curative intent over 9 days compared to gold standard therapy (positive controls) and placebo (negative control). Functional assessments of pain (quantitative sensory testing and operant test) were performed concomitantly with spinal neuropeptides quantification. At day 21 post-OA induction, PGB in MIA rats reduced tactile allodynia (P = 0.028) and improved the place escape/avoidance behaviour (P = 0.04) compared to values recorded at last time-point before initiating analgesic therapy. All spinal neuropeptide concentrations, such as substance P, calcitonin gene-related peptide, bradykinin and somatostatin, came back to normal (non-affected) rat values, compared to their increase observed in MIA rats receiving the placebo (P < 0.0001). Initiated 13 days after chemical OA induction, repeated medication with PGB provided analgesia according to quantitative sensory testing, operant test and targeted neuropeptides pain assessment methods. This report highlights the interest of using reliable and sensitive methods like targeted neuropeptide quantification to detect the analgesic effects of a test article with concomitant functional assessments of pain when studying OA pain components.

Osteoarthritic pain model influences functional outcomes and spinal neuropeptidomics: A pilot study in female rats.

Osteoarthritis, the leading cause of chronic joint pain, is studied through different animal models, but none of them is ideal in terms of reliability and translational value. In this pilot study of female rats, 3 surgical models of osteoarthritic pain, i.e., destabilization of the medial meniscus (DMM), cranial cruciate ligament transection (CCLT), and the combination of both surgical models (COMBO) and 1 chemical model [intra-articular injection of monosodium iodoacetate (MIA)] were compared for their impact on functional pain outcomes [static weight-bearing (SWB) and punctate tactile paw withdrawal threshold (PWT)] and spinal neuropeptides [substance P (SP), calcitonin gene-related peptide (CGRP), bradykinin (BK), and somatostatin (SST)]. Six rats were assigned to each model group and a sham group. Both the chemical model (MIA) and surgical COMBO model induced functional alterations in SWB and PWT, with the changes being more persistent in the surgical combination group. Both models also produced an increase in levels of pro-nociceptive and anti-nociceptive neuropeptides at different timepoints. Pain comparison with the MIA model showed the advantage of a surgical model, especially the combination of the DMM and CCLT models, whereas each surgical model alone only led to temporary functional alterations and no change in neuropeptidomics.

L'arthrose, la principale cause de douleur chronique articulaire, est étudiée à travers différents modèles animaux, mais aucun d'eux n'est idéal en termes de fiabilité et de valeur translationnelle. Trois modèles chirurgicaux de douleur arthrosique, c'est-à-dire, la déstabilisation du ménisque médial, la transsection du ligament croisé crânial et la combinaison des deux, ainsi qu'un modèle chimique (injection intraarticulaire de mono-iodoacétate de sodium) ont été comparés dans cette étude pilote chez des rattes quant à leurs impacts sur les évaluations fonctionnelles de la douleur (distribution pondérale statique, évaluation ponctuelle de l'allodynie tactile) et les neuropeptides spinaux (substance P, peptide relié au gène de la calcitonine, bradykinine et somatostatine). Six rats ont été assignés à chacun des modèles et un groupe Sham. Autant le modèle du mono-iodoacétate de sodium que celui de la combinaison chirurgicale ont tous les deux induits des altérations fonctionnelles de la distribution pondérale statique et du seuil de retrait de la patte suite à une stimulation ponctuelle tactile, mais avec des changements plus persistants dans le groupe de la combinaison chirurgicale. Ces deux modèles ont également engendré une augmentation des niveaux en neuropeptides pro-nociceptifs et anti-nociceptifs à différents moments. Un intérêt du modèle chirurgical a été démontré suite à la comparaison de la douleur avec le modèle du mono-iodoacétate de sodium, en particulier la déstabilisation du ménisque médial combinée à la transsection du ligament croisé crânial, tandis que les inductions chirurgicales unique entraînaient des altérations fonctionnelles temporaires avec aucun changement neuropeptidomique.(Traduit par les auteurs).

EEG: Characteristics of drug-induced seizures in rats, dogs and non-human primates.

Seizures are amongst the most frequent neurological issues encountered in pre-clinical safety testing. The objective was to characterize EEG morphologies and premonitory signs in drug-induced seizures in preclinical species. A comparative (inter-species) retrospective analysis for drug-induced seizures recorded by video-telemetry was conducted in rats (n = 53), dogs (n = 195), and non-human primates (n = 234). The most frequent premonitory signs were, in rats, myoclonus (100%), tremors (93%), salivation (75%), partial ptosis (58%) and chewing/bruxism (58%); in dogs, tremors (77%), ataxia/uncoordination (60%), myoclonus (45%), salivation (43%), excessive licking (38%), high vocalization (38%) and decreased activity (34%); in non-human primates, tremors (79%), decreased activity (70%), myoclonus (57%), retching/emesis (37%), hunched posture (30%) and ataxia/uncoordination (27%). Seizure duration ranged from 3 s to 14 min with an average of 46 ±â€¯21 s, comparable across species. At seizure onset, spike frequency averaged 9.4 Hz for the three species compared to 4.3 Hz at seizure end. Peak average amplitudes were attained at mid-seizure and amplitudes at seizure end decreased from peak but remained higher than onset amplitudes. Spike duration was inversely correlated with frequency and presented a crescendo pattern. Morphological characteristics can serve to refine automated EEG analysis. From a regulatory perspective, the most common paradigm is to use the most sensitive species in seizure liability studies but translational potential and clinical relevance may be under represented in the decision making process in some cases. EEG morphologies during drug-induced seizures presented remarkable similarities between species and tremors were identified as a predominant premonitory clinical sign in all species.