Gene Therapy could be a Boon to Alzheimer’s disease (AD): A first-in-human clinical trial proposed
Reporter: Dr. Premalata Pati, Ph.D., Postdoc
A recent research work performed by the Researchers at the University of California San Diego School of Medicine has shared their first-in-human Phase I clinical trial to assess the safety and viability of gene therapy to deliver a key protein into the brains of persons with Alzheimer’s Disease (AD) or Mild Cognitive Impairment (MCI), a condition that often precedes full-blown dementia.
Mark Tuszynski, M.D., Ph.D., Professor of Neuroscience and Director of the Translational Neuroscience Institute at UC San Diego and team predicted that Gene therapy could be a boon to potential treatments for the disorders like AD and MCI.
The study provides an insight into the genetic source of these mental diseases.
The roots of mental disorders have remained an enigma for so many years. Alzheimer’s disease (AD) is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. AD is a neurodegenerative condition. A buildup of plaques and tangles in the brain, along with cell death, causes memory loss and cognitive decline. In most people with the disease, those with the late-onset type – symptoms first appear in their mid-60s. Alzheimer’s disease is the mostly appearing type of dementia in patients.

Image Source: https://en.wikipedia.org/wiki/Alzheimer%27s_disease
What the study impart?
Despite decades of effort and billions of dollars of research investment, there are just mere two symptomatic treatments for AD. There is no cure or approved way to slow or stop the progression of the neurological disorder that afflicts more than 5 million Americans and is the sixth leading cause of death in the United States.
Prof. Tuszynski said gene therapy has been tested on multiple diseases and conditions, represents a different approach to a disease that requires new ways of thinking about the disease and new attempts at treatments.
The research team found that delivering the BDNF to the part of the brain that is affected earliest in Alzheimer’s disease; the entorhinal cortex and hippocampus – was able to protect from ongoing cell degeneration by reversing the loss of connections. “These trials were observed in aged rats, amyloid mice, and aged monkeys.”
The protein, called Brain-Derived Neurotrophic Factor or BDNF, a family of growth factors found in the Brain and Central Nervous System that support the survival of existing neurons and promote growth and differentiation of new neurons and synapses. BDNF is especially important in brain regions susceptible to degeneration in AD. It is normally produced throughout life in the entorhinal cortex, an important memory center in the brain and one of the first places where the effects of AD typically appear in the form of short-term memory loss. Persons with AD have diminished levels of BDNF.
However, BDNF is a large molecule and cannot pass through the Blood-Brain Barrier. As a solution, researchers will use gene therapy in which a harmless Adeno-Associated Virus (AAV2) is modified to carry the BDNF gene and injected directly into targeted regions of the brain, where researchers hope it will prompt the production of therapeutic BDNF in nearby cells.
Precautions were taken precisely in injecting the patient to avoid exposure to surrounding degenerating neurons since freely circulating BDNF can cause adverse effects, such as seizures or epileptic conditions.
The recent research and study speculate a safe and feasible assessment of the AAV2-BDNF pathway in humans. A previous gene therapy trial from 2001 to 2012 using AAV2 and a different protein called Nerve Growth Factor (NGF) was carried out by Prof. Tuszynski and team where they observed immense growth, axonal sprouting, and activation of functional markers in the brains of participants.
He also shared that “The BDNF gene therapy trial in AD represents an advancement over the earlier NGF trial, BDNF is a more potent growth factor than NGF for neural circuits that degenerate in AD. Besides, new methods for delivering BDNF will more effectively deliver and distribute it into the entorhinal cortex and hippocampus.”
The research team hopes that the three-year-long trial will recruit 12 participants with either diagnosed AD or MCI to receive AAV2-BDNF treatment, with another 12 persons serving as comparative controls over that period.
The researchers have plans to build on recent successes of gene therapy in other diseases, including a breakthrough success in the treatment of congenital weakness in infants (spinal muscular atrophy) and blindness (Leber Hereditary Optic Neuropathy, a form of retinitis pigmentosa).”
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