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Can Alzheimer's damage to the brain be repaired?

repair jobIn my recent Stanford Medicine article about Alzheimer's research, called "Rethinking Alzheimer's," I chronicled a variety of new approaches by Stanford scientists to nipping Alzheimer's in the bud by discovering what's gone wrong at the molecular level long before more obvious symptoms of the disorder emerge.

But Stanford neuroscientist Frank Longo, MD, PhD, a practicing clinician as well as a researcher, has another concern. In my article, I quoted him as saying:

Even if we could stop new Alzheimer’s cases in their tracks, there will always be patients walking in who already have severe symptoms. And I don’t think they should be forgotten.

A study by Longo and his colleagues, which just went into print in the Journal of Alzheimer's Disease, addresses this concern. Longo has pioneered the development of small-molecule drugs that might be able to restore nerve cells frayed by conditions such as Alzheimer’s.

Nerve cells in distress can often be saved from going down the tubes if they get the right medicine. Fortunately, the brain (like many other organs in the body) makes a number of its own medicines, including ones called growth factors. Unfortunately, these growth factors are so huge that they won't easily cross the blood-brain barrier. So, the medical/scientific establishment can't simply synthesize them, stick them into an artery in a patient's arm and let them migrate to the site of brain injury or degeneration and repair the damage. Plus, growth factors can affect damaged nerve cells in multiple ways, and not always benign ones.

The Longo group's study showed that - in mice, at least -  a growth-factor-mimicking small-molecule drug (at the moment, alluded to merely by the unromantic alphanumeric LM11A-31) could counteract a number of key Alzheimer degenerative mechanisms, notably the loss of all-important contacts (called synapses) via which nerve cells transmit signals to one another.

Synapses are the soldier joints that wire together the brain's nerve circuitry. In response to our experience, synapses are constantly springing forth, enlarging and strengthening, diminishing and weakening, and disappearing.They are crucial to memory, thought, learning and daydreaming, not to mention emotion and, for that matter, motion. So their massive loss -- which in the case of Alzheimer's disease is a defining feature - is devastating.

In addition to repairing nerve-cells, the compound also appeared to exert a calming effect on angry astrocytes and  microglia, two additional kinds of cells in the brain that, when angered, can produce inflammation and tissue damage in that organ. Perhaps most promising of all, LM11A-31 appeared to help the mice remember where things are and what nasty things to avoid.

Previously: Stanford's brightest lights reveal new insights into early underpinnings of Alzheimer's, Stanford neuroscientist discusses the coming dementia epidemic and Drug found effective in two mouse models of Huntington's disease
Photo by Bruce Turner

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