Preclinical epilepsy-related research with InnoSer
Broadly speaking, epilepsy is a large spectrum of distinct epileptic syndromes that differ in their etiologies, mechanisms, pathophysiological processes, associated comorbidities, and response profile to available therapies. Out of these epilepsy syndromes, approximately 30% of epilepsies are estimated to have a genetic etiology; examples of which are developmental and epileptic encephalopathies (DEE) such as Dravet syndrome, Rett syndrome, STXBP1 infantile encephalopathy and many other syndromes. The genetic etiology of epileptic syndromes opens up the avenue toward disease-modifying anti-epileptogenic therapies, offering patients with possibility of curative treatments.
The goal of preclinical epilepsy research is to advance laboratory findings towards clinical application by testing putative treatments in animal models with relevant genetic mutations associated with a given epilepsy syndrome. However, to ensure that preclinical discoveries are reliably translated to the clinic, it is imperative that preclinical research needs to be performed under standardized conditions with well-established mouse models with clear epilepsy-related abnormalities in the EEG. Performing efficacy studies requires validated mouse models of epilepsy, standardized experimental protocols, access to multiple technologies and behavioral testing protocols.
In this regard, partnering up with a specialized epilepsy preclinical contract research organization (CRO), may help you accelerate your novel anti-epileptic therapy to the clinic with confidence. Continue reading this blog post to learn more about the advantages of partnering up with InnoSer for your preclinical epilepsy research. In this blog post, we outline InnoSer’s epilepsy capabilities with InnoSer’s epileptic encephalopathy Stxbp1 mouse model serving as an example epilepsy model.
InnoSer’s preclinical epilepsy research models
Preclinical epilepsy research models provide important insights on disease mechanisms, and most importantly therapy targets and efficacy and safety profiles of novel candidate treatments for epilepsies and seizures. A suitable mouse model of epilepsy should replicate the etiology of human disease, exhibit similar disease phenotype as in humans, and can be used to test efficacy treatments i.e., they should respond to currently available gold-standard anti-epileptic compounds.
InnoSer offers specialized epilepsy preclinical research services using a unique Stxbp1+/- mouse. In this model, the loss of function of the Stxbp1 protein (also known as Munc 18-1) recapitulates several key disease characteristics observed in epileptic encephalopathy patients, including epileptic-like activity, cognitive impairments and behavioral disturbances, such as anxiety and hyperactivity. To read more about the Stxbp1 mouse model, visit our Stxbp1 mouse model overview page or download a comprehensive model leaflet here. Stxbp1 mouse model characteristics have been extensively characterized, peer-reviewed, and published (Kovacevic et al. 2018).
Our experience in modeling epilepsy, however, extends beyond this model, and we offer many relevant readouts (breeding, EEG, video scoring of seizures, behavior) that can be applied to other epilepsy-related models. The same platform can be used for other indications such as Dravet (using an Scn1a model), Rett syndrome (Mecp2 model), Tuberous sclerosis (Tsc1 model) Angelman syndrome (Ube3a model) and others. If you’re interested in other mouse models, please contact InnoSer’s neurology team by submitting your request here.
Breeding and housing of preclinical epilepsy research models at InnoSer
InnoSer has the capacity to breed and house mouse models of epilepsy either for your research or alternatively before performing efficacy research at InnoSer. InnoSer’s strategic location in the heart of Europe in Belgium allows us to breed and maintain your specific mouse colonies and ship them out to your facilities before you commence research. This in turn helps you save maintenance costs associated with breeding and housing mouse colonies. Breeding and housing epilepsy mouse research models at InnoSer also allows us to start prophylactic treatments, which can start as early as post-natal day 1 (PND1), which can prove to be especially useful when you’re working with gene therapy treatments. Mice are housed in SPF facilities, according to the FELASA 2014 guideline recommendations. Read more about InnoSer’s standards and housing capabilities here.
Electroencephalography (EEG) as a highly translatable readout in epilepsy mouse models
Electroencephalography (EEG) is the main tool used to clinically diagnose seizures and epilepsy – also commonly used in rodent disease models of epilepsy. The use of clinically relevant readouts in preclinical research – such as EEG – is highly encouraged as this can help increase your confidence in your test compound’s efficacy profile, accelerating its way to the clinic and patients. By implanting electrodes superficially on the cortex of mice, intracranial EEG is performed in freely moving mice to record epileptic and epileptic-like events from the brain.
As in humans, epileptic-like events and seizures are typically detected and classified using a combination of EEG and behavioral signs such as convulsions or myoclonic jerks. At InnoSer, we utilize a combination of EEG, 24/7 video monitoring in automated home cages and accelerometry to characterize efficacy profile of novel anti-epileptic treatments (Figure 1). In-cage monitoring allows us to continuously assess unforced behavior in mice; both continuous video capture and animal movement tracking present opportunities for robust, non-invasive detection of epileptic-like activity.
FIGURE 1. Experimental setup for recording epileptic-like activity in mouse models of epilepsy. (A) Neuronal activity is assessed using a wireless EEG recorder with built-in accelerometer sensor. Mice can be recorded in an automated home-cage (PhenoTyperTM) that simultaneously detects movement following epileptic events such as spike-wave discharges (SWDs) in Stxbp1 +/- mouse model. (B-D) EEG signal, accelerometer trace and video recordings of an Stxbp1+/-mouse confirm epileptic-like phenotype in Stxbp1+/-. (B) SWDs are observed when mouse is at rest (C) SWDs can be followed by jerky movements such as a twitch recorded on accelerometer and video recording. (D) SWDs are also detectable when the mouse is moving.
The Stxbp1 +/- mouse model exhibits epileptic-like activity in EEG (SWDs), and muscle twitches detected in EMG and/or on continuous video recording systems. Epileptic-like activity is present early in on in Stxbp1 mouse model, meaning that novel therapies can be either prophylactic or symptomatic. Moreover, mice exhibit constant epilepsy-related activity, allowing longitudinal studies to be performed, which may be especially important for evaluation of disease-modifying drugs (Figure 2). Moreover, in this model, epileptic activity is correlated to increased expression of the neuronal marker c-Fos (Kovacevic et al. 2018). The clinically used anti-epileptic drug (AED) levetiracetam as well as Lamotrigine reduce epileptic-like activity in EEG 1 (Figure 3), confirming the use of this mouse model for efficacy testing alongside the chosen positive control compounds.
FIGURE 2. Stxbp1 +/- mice aged from 16 weeks to 20 weeks show stable epileptic-like phenotype. Average frequency of SWDs per hour in the Stxbp1 +/- mice assessed over a period of several weeks (MEAN ± SEM).
FIGURE 3. The epilepsy-like phenotype in Stxbp1 +/- mice is suppressed with standard care AEDs Levetiracetam and Lamotrigine. Average frequency of detected SWDs during 6 hours of video recording following administration of saline, Levetiracetam (50 mg/kg, i.p,) and Lamotrigine (50 mg/kg, i.p.) (**P<0.01 saline vs Levetiracetam; ***P<0.001 saline vs Lamotrigine).
Behavioral research of mouse models of epilepsy
Epilepsy is a spectrum of disorders that are not only characterized by spontaneous and recurrent seizures, but also cognitive, social and behavioral deficits such as those observed in multiple epileptic encephalopathy syndromes. Therefore, preclinical research should be carried out in mouse models whereby relevant behavioral deficits can be observed to enhance the translational value of such study types. To learn more about InnoSer’s behavioral testing expertise, please visit our behavioral tests webpage overview here.
The Stxbp1 mouse model recapitulates several key disease characteristics observed in patients, including epileptic-like activity, cognitive impairments and behavioral disturbances, such as anxiety and hyperactivity (Figure 4). Furthermore, the model shows robust and reproducible cognitive impairment and behavioural disturbances, confirming its use beyond traditional epilepsy research focused solely on EEG-related outcomes.
FIGURE 4. Stxbp1+/- mice mimic cognitive impairments symptoms observed in epileptic patients that can be detected during a fear conditioning assay. In contextual fear conditioning, mice learn to pair an unconditioned stimulus with an aversive context. The so-called freezing response of the mouse is monitored to assess the extent to which the unconditioned stimulus is paired with the context. This test is both a measure of anxiety and cognition (learning and memory).
PK/PD profiling in mouse models of epilepsy
PK/PD studies should be performed prior to commencing efficacy studies to obtain the correct dosages of your novel compounds. With InnoSer’s integrated pharmacology platform, you can get access to various pharmacology services ranging from PK/PD profiling, ADME/DMPK, biodistribtion as well as early-stage toxicology to comprehensively evaluate the therapeutic potential of your anti-epileptic compound. Performing combined PK/PD profiling and efficacy studies at InnoSer is highly advantageous as follow-up efficacy studies can be started rapidly, with high capacities to run multi-arm trials due to our large in-house breeding colonies to help you select the optimal candidate compound. Contact us for more information about performing pharmacology studies here.
Designing the right study design for your epilepsy research
As a preclinical epilepsy research CRO, InnoSer works with well-established validated mouse model of epilepsy, standardized data collection system, validated positive controls as well as with neurology experts who partner with you to provide a collaborative approach for your research. InnoSer partners with you to help you design your study based on our experience or alternatively offers you flexible starting times in case your study design is already finalized. Our study directors take a collaborative approach for your study, providing regular communications and updates, as well as guidance on future studies. InnoSer has capacity to work with multiple therapy types ranging from small molecule drugs, as well as working with platforms (e.g., RNA, ASOs, gene therapy approaches). Furthermore, InnoSer’s preclinical research services span beyond efficacy studies and also include general drug development services such as PK/PD profiling and early-stage toxicology studies.
Interested in partnering with InnoSer for your preclinical epilepsy research? Do not hesitate to get into contact with one of our neurology study directors to discuss the possibilities of outsourcing your research to InnoSer. Submit your request still today by clicking here.