Animal Defenders International

 

Animal Defenders International

How scientists are treating Alzheimer’s in mice but not humans

Posted: 23 September 2019. Updated: 24 September 2019

Ahead of World Alzheimer’s Day on Saturday, September 21, Animal Defenders International (ADI) is highlighting how none of the 500 therapies shown to improve Alzheimer’s symptoms in animal models have translated to successful treatments for human sufferers of the disease.

An estimated 50 million people are living with dementia worldwide. Alzheimer’s disease is a specific form of dementia affecting an estimated 5.8 million people in the US.

For decades, attempts have been made to discover the causes of Alzheimer’s and look for potential therapies, using animals such as mice, who have been genetically modified to suffer Alzheimer’s-like symptoms. However, these ‘models’ of the disease are not the same as the disease in humans. These differences, together with the underlying differences between mice and humans, make for crucial problems in applying such research to people.

It should therefore come as no surprise that a review of Alzheimer’s animal models has concluded that no animal models represent the disease fully and “no animal models exist which are predictive for the efficacy of interventions for Alzheimer’s disease.”

Jan Creamer, President of Animal Defenders International, said, “Advanced, human-based research techniques show the way to understanding Alzheimer’s, helping sufferers of the disease. When genetically engineered in animals who do not naturally suffer from Alzheimer’s, the disease is not the same and combined with species differences results can be, and are, misleading.”

“We’ve cured mice engineered with this disease over 500 times. The mouse models don’t translate into humans.”Chief Science Officer, Alzheimer’s Drug Discovery Foundation.

Many scientists are finding the way forward with advanced scientific techniques such as:

•Human patient tissue samples to study genetics of the disease
•Study of tissue biobanks, which contain the data from thousands of healthy volunteers, to help identify Alzheimer’s risk
•Research with Alzheimer’s patients which allow studies of disease progression
•Post-mortem studies of the diseased brain
•Use of human stem cell for drug discovery
•Population studies to explore connections between Alzheimer’s disease and environmental or lifestyle factors

Human studies have helped identify a number of lifestyle risk factors that could reduce the risk of disease. Evidence suggests a link between heart disease and the development of Alzheimer’s, with high calorie intake also associated with a higher risk. Increasing physical activity and certain foods like nuts, fruit, and dark, leafy vegetables, and avoiding red meat, butter, and other dairy products could reduce risk of disease later in life.

These non-animal alternatives avoid the fundamental differences between species in their reaction to therapies and misleading results from animal models. For example, in rodent models, animals show very little brain cell loss, unlike in Alzheimer’s disease.

Examples of potential Alzheimer’s treatments in animals, that have failed when applied to humans, include:

•BACE - A class of drug which had a positive effect on the brains of Alzheimer’s mouse models, but for which clinical trials were abandoned after it was found to be “completely useless” at slowing or preventing the disease in patients.
•Azeliragon - This new drug was tested in transgenic mice with Alzheimer’s symptoms leading researchers to suggest it could “slow cognitive decline and improve cerebral blood flow” in patients with mild disease. The drug failed with clinical trials terminated early.

The use of animal models are not only misleading, they cause animals to suffer too.

Media contacts:
US:
Lesley McCave, ADI Communications Director: (323) 935-2234/(323) 804-9920, or mediadesk@ad-international.org

UK:
Angie Greenaway, 020 7630 3344 or 07785 552548 prdesk@ad-international.org

© Animal Defenders International 2019