EFFICACY STUDIES

EVALUATING THERAPEUTIC EFFICACY

MODELS OF HUMAN DISEASE

Efficacy studies are designed to evaluate therapeutic interventions using validated cell culture or animal models that simulate human diseases. At Biotest Facility, we have extensive experience with a number of efficacy models, addressing a range of human disorders. We also offer the development of novel animal models tailored to specific research needs, either by conducting thorough literature reviews or by adapting models from the laboratories of our sponsors or their collaborators.

Disease models can be induced using various methods, including cancer cell or tissue transplantation, surgical procedures, chemical agents, special diets, infectious agents, immunisations, and genetic modifications. Successful efficacy studies rely on a comprehensive understanding of complex mechanisms, including host genetics, disease aetiology and pathogenesis, drug formulation, administration routes, dosing regimens, and the availability of suitable reference treatments.

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Translational rodent models link basic research to clinical application by replicating human disease. Their genetic and physiological similarity to humans enables controlled, predictive studies, ethically advancing treatments while minimising risks before human trials.

EXAMPLES OF MODELS

AUTOIMMUNE DISORDERS

Disease models can be established through various methods. Immunisation-based models include Myasthenia Gravis (MG) in rats and mice, induced by immunisation with recombinant acetylcholine receptor (AChR). Other examples of immunisation-based models are Arthritis in mice, induced by immunisation with collagen II, and Multiple Sclerosis, induced by immunising mice with central nervous system (CNS) tissue.

CHEMICALLY INDUCED MODELS OF DISEASE

Chemically induced models provide another approach. Examples include Vitiligo (induced by monobenzone in mice), 7,12-Dimethylbenz[a]anthracene (DMBA)-induced mammary cancer, and Colitis (induced by dextran sulfate sodium, DSS).

CANCER XENOGRAFT AND SYNGENEIC GRAFT

Cancer models include the transplantation of human-derived cancer cells into immunodeficient mice or the use of syngeneic tumour cells in immunocompetent mice. These cancer models are referred to as xenograft or allograft models, respectively. Host animals may range from wild-type mice to humanised mice with tailored immune systems to better mimic human disease.

IMMUNOONCOLOGY

Immuno-oncology (IO) focuses on using the immune system to fight cancer, aiming for precise targeting with fewer side effects compared to traditional treatments. This involves studying immune-tumour interactions and developing therapies that restore or enhance the immune system’s ability to target cancer.

Our Animal Biosafety Level 1 (ABSL-1) facility supports immuno-oncology studies with a specialised cell laboratory for cultivating and conditioning both cancer and immune cells. This enables tumour cell graft preparation and immune cell activation or expansion, providing a controlled environment for testing innovative immune therapies.

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Immuno-oncology transforms cancer treatment by leveraging the immune system—a natural precision weapon. From early breakthroughs in checkpoint inhibitors to today’s advanced cell therapies, IO has the potential to redefine cancer care.

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At the core of many disease models lies genetic engineering, where modifications such as knockout, transgenic, and conditional mutants enable the study of human conditions and intricate biological pathways.

GENETIC DISEASE MODELS

Genetically engineered models constitute a significant proportion of rodent disease models and are invaluable tools in preclinical research. Advances in genetic engineering techniques, such as CRISPR/Cas9 (a method for precisely editing genes), have significantly reduced the time required to generate new models, although extensive model characterisation still remains a requirement. Models include knockout mice, which lack specific genes, transgenic models with introduced human genes to study human-specific biological processes and molecular interactions, and conditional mutants, where gene expression can be precisely controlled by external factors.

These models provide powerful insights into disease mechanisms and therapeutic interventions, enabling researchers to investigate complex biological pathways and test novel treatments in a highly targeted manner. By combining advanced genetic models with robust experimental design and modern analytical approaches, researchers can drive discoveries that rapidly translate into meaningful clinical progress.

DISEASES OF THE CNS

The central nervous system (CNS) is a highly complex and tightly regulated system, serving as the command centre for motor- and cognitive functions. Genetic diseases and neurological disorders affecting the CNS present significant challenges for medical research due to the protected nature of this system. Advances in precision medicine have opened new avenues for targeting CNS disorders, with antisense oligo nucleotides (ASOs) and RNA interference (RNAi) emerging as promising therapeutic strategies. At Biotest Facility, we leverage cutting-edge methodologies to support the preclinical evaluation of these novel approaches.

DIRECT DOSING TO THE CNS

Therapeutic interventions for the CNS require circumvention of the blood-brain barrier (BBB), which restricts the entry of most drugs into the brain. For compounds like ASOs or RNAi therapies, direct delivery to the CNS ensures effective drug concentration at the site of action.

At Biotest Facility, we have the expertise to administer test articles directly to the CNS of anaesthetised mice. This includes intracerebroventricular (ICV) injections, which allow precise delivery of therapeutic agents into the cerebrospinal fluid (CSF).

APPLICATIONS OF DIRECT CNS DELIVERY

  • Genetic Disorders: Diseases such as Huntington’s disease, spinal muscular atrophy (SMA), and certain forms of amyotrophic lateral sclerosis (ALS) are caused by specific genetic mutations. ASOs and RNAi therapies can be directly administered to modulate gene expression, offering potential for a targeted approach to mitigate disease progression.
  • Neurological Conditions: Disorders such as Alzheimer’s disease, Parkinson’s disease, and epilepsy often involve localised pathologies within the CNS. Direct delivery of therapeutic agents may be an avenue to reducing off-target effects and improving efficacy.
  • Drug Testing for CNS-Specific Therapies: When a test drug is intended for dosing to the CNS—whether for addressing neurodegenerative diseases, rare genetic disorders, or CNS infections—direct CNS dosing ensures an accurate preclinical evaluation of its safety, biodistribution, and therapeutic potential.

CSF SAMPLING FOR BIOMARKER ANALYSIS

In addition to direct drug delivery, we also offer the capability to collect CSF samples from mice and rats, for example for biomarker analysis. CSF is a vital diagnostic and research tool, providing insight into the biochemical and pathological processes occurring in the CNS.

APPLICATIONS OF CSF ANALYSIS

  • Pharmacokinetic (PK) and Pharmacodynamic (PD) Studies: Measuring drug concentration and activity in the CSF provides critical data on the distribution, metabolism, and efficacy of CNS-targeted therapies.
  • Biomarker Discovery and Validation: CSF biomarkers can serve as indicators of disease progression or therapeutic response.
  • Safety Assessments: Monitoring CSF composition for potential adverse effects, such as neuroinflammation or toxicity, helps ensure the safety profile of new therapeutics.

DRIVING PROGRESS IN CNS RESEARCH

The ability to dose directly to the mouse brain and sample CSF from rodents enables precise evaluation of therapeutic strategies for conditions with limited treatment options, providing hope for patients suffering from devastating CNS disorders. By refining our understanding of how these therapies interact with the CNS, we contribute to the development of safer and more effective treatments that can transform lives.

MYASTHENIA GRAVIS

Myasthenia Gravis (MG) is an autoimmune disease characterised by muscle weakness and fatigue, primarily caused by autoantibodies targeting the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction (NMJ). A subgroup of MG (5-8% of patients) involves antibodies targeting muscle-specific receptor tyrosine kinase (MuSK). Patients with MuSK-MG are often more severely affected and less responsive to current treatments.

Experimental Autoimmune Myasthenia Gravis (EAMG) is a well-established model that replicates many aspects of human MG. EAMG is typically induced in animals by immunisation with AChR or MuSK antigens.

Our facility specialises in two specific rat models for studying Myasthenia Gravis:

  • An AChR-induced EAMG model, in which rats are immunised with recombinant AChR antigens. The antigen we typically use is a chimeric human-snail protein, leading to the development of disease symptoms analogous to those seen in human MG.
  • A MuSK peptide-induced EAMG model, particularly relevant for studying the severe MuSK-MG subtype. The antigen in this model is a synthetic peptide.

    COMPOUND MUSCLE ACTION POTENTIAL

    A hallmark feature of Myasthenia Gravis is the decrement in compound muscle action potential (CMAP) upon repeated activation. This directly reflects the dysfunction at the neuromuscular junction. The decrement occurs as a result of impaired transmission of nerve impulses to the muscle due to the dysfunction of acetylcholine receptors (AChR) at the NMJ. As a result, there is reduced neuromuscular transmission, leading to weaker muscle contractions and progressive muscle fatigue. The CMAP is an important diagnostic measure, as the decrease in its amplitude is indicative of the level of dysfunction.

    We measure CMAP directly in vivo using electromyography (EMG) apparatus. This allows for real-time assessment of neuromuscular transmission and the degree of dysfunction at the NMJ, providing a valuable quantitative measure of disease progression in our animal models.

      FUNCTIONAL PARAMETERS

      In addition to electrophysiological measurements, we also assess the functional impairment caused by Myasthenia Gravis in our quantitative motor performance laboratory. Tests of functional impairment evaluate the overall physical capability of the animals and provide insight into the severity of the disease. Tests of functional impairment include the following:

      • Rotarod Test: This test evaluates the animal’s motor coordination and balance. The rat is placed on a rotating rod, and the time it remains on the rod before falling off is recorded. A decrease in balance time can be indicative of motor deficits, correlating in the EAMG model with  progression of MG.

      • Grip Strength Test: This test measures the animal’s ability to grip and hold onto a grid coupled to a force transducer. The strength of the grip is quantified by measuring the force exerted by the animal. A reduction in grip strength is a clear indication of muscle weakness, and of disease progression in the EAMG rat model.

      • Wire Hanging Test: This test evaluates neuromuscular strength by measuring the time an animal can hold onto a wire cage lid before falling. The animal is placed on the lid, which is then shaken to encourage grip, followed by the lid being slowly inverted at a height of 0.5–0.6 m above a soft surface. The time until the animal falls is recorded, with a cut-off time depending on the model.

      Together, these functional assessments, alongside CMAP measurements, provide a comprehensive picture of the motor impairment and neuromuscular dysfunction in MG and EAMG models, supporting the evaluation of potential therapeutic interventions.

         “…Providing in vivo studies in rodent disease models, with expertise in both molecular analyses and specialised functional assessments…”

        Preclinical in vivo studies at Biotest Facility

        STUDIES IN AGED ANIMALS

        Research involving aged animals, e.g. mice up to 2 years old, plays a critical role in understanding age-related diseases and therapeutic interventions. At Biotest Facility, we have extensive experience in designing and conducting studies that leverage aged animal models to explore the complexities of ageing biology. These models are invaluable for investigating conditions such as neurodegeneration, cancer, metabolic disorders, and immunosenescence, providing insights that are directly relevant to the ageing human population.

        Our expertise includes the meticulous care and monitoring required for aged mice, ensuring consistent health and welfare throughout the study. We optimise study designs to account for the unique physiology of older animals, delivering reliable and translational results for preclinical research.

        Preclinical studies in aged mice

        Using aged mice in preclinical studies not only models human ageing but also uncovers age-specific side effects or diminished efficacy of treatments, offering a more comprehensive understanding of therapeutic outcomes.

        CONTACT US REGARDING DISEASE MODELS

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