Most present day drugs are developed through a trial-and-error approach, which often don’t reveal why a certain drug elicits an effect. But the expanding knowledge gained from new methods of molecular biology, makes it possible to design and produce safer and more effective drugs. One of the promising candidates for new drug therapies, are trophic factors.

What are trophic factors?

Neuroscience research has lead to the identification of several growth factors, or trophic factors, in the brain, which control the development and survival of specific groups of neurons. Once the actions and receptors of these molecules are identified, and the genes cloned, procedures can be developed to modify trophic factor regulated functions in ways that might be useful in the treatment of neurological disorders.

As soon as a trophic factor for a particular neuron has been found, copies of that factor can be genetically targeted to the area of the brain where this type of cell has died. Such a treatment might not cure the disease, but is certainly able to improve the symptoms and delay the progression.

Nerve Growth Factor

One of these factors, nerve growth factor (NGF), has already demonstrated its possible value. When infused in the brain of rats, it prevented cell death and stimulated regeneration of damaged neurons that are known to cause Alzheimer’s disease. Aged animals with learning and memory problems that were treated with NGF, were found to be able to remember a maze as well as healthy rats. NGF, that slows the destruction of neurons that use acetylcholine, also holds promise for slowing the memory deficits associated with normal aging.

New Factors

• Recently, several new factors have been identified. Before these can be useful for therapy, scientists must first understand how they could influence neurons. In the future, Alzheimer’s disease, Parkinson’s disease and ALS could all be treated with trophic factors.
• Furthermore, researchers have shown that a neutralization of inhibitory molecules can help repair damaged nerve fiber tracts in the spinal cords. Using antibodies to Nogo-A, a protein that inhibits nerve regeneration, some nerves of damaged spinal cords were able to grow again in rats. These treated rats showed great improvements in their ability to walk after spinal cord damage. Within two or three weeks, some fibers grew to the lower level of the spinal cord and, in some animals, along its whole length. This type of research could potentially have clinical implications for brain- or spinal cord- damaged people.