Neurogenesis

Editor's Memo -- Practical Pain Management

by Forest A. Tennant, MD, DrPH

Neurogenesis is simply the growth of nerves. While acute pain may be the result of an offending stimulus to healthy nerves, chronic pain invariably results from some nerve dysfunction or “damage.” Nerve repair or regrowth must therefore occur if cure, resolution, or amelioration is to permanently happen. Surprisingly, the term for this process, “neurogenesis,” hasn’t yet entered the lexicon of pain treatment. I don’t recall the term ever being used in a paper submitted to this journal nor do I recall it being used in any of the many research abstracts I’ve reviewed at the numerous pain conferences I’ve attended in recent years.

To date, the concept and term ‘neurogenesis’ has remained the purview of a handful of dedicated animal and bench scientists. This must change. Why? Contrary to the antiquated belief that damaged nerves, including brain tissue, can’t regenerate, regrow, or otherwise undergo neurogenesis, it’s happening every day in every pain practice in the country. Just recall your own conversations and observations of chronic pain patients. Look at how many no longer have constant pain but now have a few pain free days or hours. Every physician now knows of some chronic pain patients who have so reduced their pain levels that they have totally stopped opioid drugs. Look at the incredible number of pain patients who are progressively improving their quality of life because their pain has permanently reduced in severity. Folks, this is neurogenesis at its best!

Early research has now clearly identified nerve tissue lesions in chronic pain states.1 While investigations involving nerve tissue defects and neurogenesis are just beginning, it is rather axiomatic that adequate pain control may not only prevent nerve tissue lesions but pain treatment—including pharmacologic agents—may act as a “splint” that allows nerve tissue to regenerate. Treatment agents, such serotonergic antidepressants in animal research, may even stimulate neurogenesis.

What’s now needed is an understanding of the mechanism of neurogenesis. Clearly, the current standard chronic pain treatment modalities of medication, exercise, psychotherapy, hormone replacement, and dietary supplementation aren’t just symptomatic relief. Neurogenesis must be occurring. Physicians everywhere are getting results that indicate organic, physiologic changes have taken place. A lot of the new physiologic techniques, including low level laser and electrical stimulation, may prove to greatly enhance neurogenesis.

This, however, does not invalidate the original prescription of opioids when the patient does get better. It’s amazing, for example, how many patients are told they didn’t really need opioids or muscle relaxants in the first place since their pain reduced over time. The fact may be that the patient’s medication and symptom relief may have allowed a suppressed immune system to gear up and promote neurogenesis. It may well be that current concerns over opioid overuse is really related to neurogenesis. After all, a regrown bunch of nerves and receptors may not need the same amount of opioid today that they did a few months ago. In fact, a bunch of regenerated nerves might just adversely react to a former higher dosage of medication.

The bottom line here is straightforward. We should clearly enunciate for public and patient that our first goal of chronic pain treatment is to provide immediate humanitarian relief of suffering, but the long-term goal is neurogenesis. While the term neurogenesis may initially be a little tough to pronounce for non-medical persons, patients will gladly master it. After all, neurogenesis is truly the word of hope for millions of chronic pain sufferers.

—Forest A. Tennant, MD, DrPH Editor in Chief