On Pumping Medication Directly Into the Brain
"Cartoons and Poems following each article are created and copyrighted by Dr. Ackerman and cannot be copied or reproduced without his permission."

Microdialysis is a relatively new way to pump medication directly into those regions of the brain where they might be needed. This is a follow-up of a concept that appears to hold considerable promise for sufferers of Parkinson's disease. The research is still in its infancy, but its proponents, neurologists from the Frenchay Hospital in Bristol, have actually achieved results that went way beyond their own expectations. Their technique, which they reported at the 54th annual meeting of the American Neurological Association, in Denver, Colorado, was similar. They implanted catheters into the brains of five patients. One of the researchers, Dr. Gill, characterized the method as follows: "We can deliver a drug very precisely to areas in the brain in the concentrations that we need to cause recovery, and we can control that very precisely." The two pumps for the catheters were implanted in the wall of the abdomen where they worked continuously. Before I discuss the results of this hope-filled research I would like to provide you with a bit more insight into what is believed to go on in the brains of Parkinson's disease patients as compared to normals, so that you might better understand why this technique might be promising.

The information that our bodies need in order to control our movements is stored in a central area of the brain, called the striatum. When this information is required by the body for control of balance and coordination a second area of the brain comes into play. This area, the substantia nigra, assists the striatum in sending out the necessary commands. These signals are passed into the spinal cord, which then delivers them to the appropriate muscles. However, none of this can occur without chemicals called neurotransmitters that pass the messages from one nerve cell to another across a connection called a synapse. One of the most important neurotransmitters is dopamine, which is manufactured in the substantia nigra. Nerve cells actually pass the dopamine by placing it in packets that move to the nerve cell endings, open a "window," and release the dopamine particles into the synapse. Other nerve cells are specialized to use another messenger, acetylcholine. The two transmitters correlate with one another in a balancing act in order to create smooth muscle action. In Parkinson's disease this correlation is disturbed due to deficiency of dopamine in the dorsal putamen of the brain. If this deficiency can be corrected, reason Parkinson's disease researchers, it may be possible to alleviate the poor coordination resulting in the shaking experienced by their patients.

The study was limited to the unilateral form of the disease. All patients chosen were in stage III (Hoehn and Yahr) and ranged in age from 46 to 62 years. Neurosurgeons placed the catheters in the putamen of each patient so that the chemical could be delivered directly to the deficient region. However, the chemical used was actually glial-derived neurotrophic factor needed for the development of dopaminergic neurons. Thus the actual dopamine resulting is a product of the patient's own nerve cells that have been stimulated to create it.

If the preliminary results can be counted on to continue into later studies, this method of treating Parkinson's disease may present opportunities for considerable future success, not only for this disease but also for numerous others. New therapies rarely work on all patients in a study; however, all five patients treated this way showed marked improvement. Everyone walked better. Several other measures used to determine progress, including the Parkinson's disease rating scale, also noted improvement. One individual realized that his sense of smell had returned. When certain vital measurements were calculated, it was apparent that these results were better than anything ever seen before, including cell transplantation. Perhaps the most thrilling aspect was the speed with which beneficial results took place. Within one or two months patients reported significant changes. This was much quicker than the many months to years originally expected. The next measurement of success awaits scanning of the affected areas of the brain using positron emission tomography.

In a former article about microdialysis I pointed to the rather annoying concept of having needles placed in your brain for any prolonged period of time. I imagine that I would be tempted to withdraw my objections if a loved-one or I were to be debilitated by Parkinson's disease, since this therapy seems to promise at least a marked symptomatic improvement if not a complete cure. I can't imagine that any reasonable individual would be likely to raise strong objections to the procedure unless it turns out to be much too costly for them to consider.

Cartoons and Poems following each article are created and copyrighted by Dr. Ackerman and cannot be copied or reproduced without his permission. Copyright © 2006 by Marvin Ackerman, M.D.

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