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|Prof. Richard Harris (1)|
About Prof. Richard Harris
University of Michigan,
You are the pioneer in the field of molecular neuro-imaging applied to acupuncture and chronic pain including fibromyalgia. The audience are not familiar with the molecular neuro-imaging. What is molecular neuro-imaging?
Sure. There’s a couple different techniques that researchers use to investigate molecular abnormalities or pathological factors in chronic pain patients, as well as treating them with different interventions like acupuncture or acupressure to see how that affects neurochemistry.
The two main techniques are positron emission tomography which uses radioactive molecules and assesses either neurotransmitter levels or receptor binding abilities. So that’s positron emission tomography or PET. The other chemical imaging technique is called proton magnetic resonance spectroscopy and it doesn’t use radioactive substances, so you can do multiple sessions with the same individual without having the problem of radiation accumulation. So proton magnetic resonance spectroscopy is really nice for that. And with proton magnetic resonance spectroscopy, you typically are looking at either Glutamate or GABA, the brain’s major excitatory or inhibitory neurotransmitters respectively. So, those are the two main techniques.
What brought you to the acupuncture research?
So, my basic training is in electrophysiology. I started out as a graduate student in an electrophysiology lab and I studied ion channel kinetics and permeation properties of ion channels. So I was doing a lot of basic science for my PhD. But during that time, I started learning meditations, things like Qigong and Taichi and martial arts and I was really interested in how those things worked. Because I felt that they were changing me both physically, mentally and emotionally. I wanted to try to understand that. I got interested in acupuncture because I thought acupuncture would be a controlled way of studying it. And it turned out that there was a lab in Washington D.C. where I was learning acupuncture. There was a lab that had a clinical trial. They had a grant to study fibromyalgia patients with acupuncture. They needed a research assistant, so I just joined the lab and became a research assistant and performed acupuncture research on that clinical trial during the day and then at night I learned how to do acupuncture clinically to treat patients at the same time, and so that was how I got involved. So kind of, it was very serendipitous. I didn’t really plan it out that way. It just happened. And I was very, very fortunate and lucky.
You have been a lot of beautiful research and published many wonderful papers. Can you give us the… what is the most important findings you’ve done in acupuncture research?
So I’d have to say I haven’t published a lot in acupuncture but I’ve published a little. One of the studies which I think has gained a lot of attention was my mu-opioid receptor PET study in fibromyalgia patients where we found that sham acupuncture and verum acupuncture induce the same analgesic response but the mechanisms by which they engender that response seemed to be quite different. The sham acupuncture seemed to increase the release of endogenous opioids whereas the verum acupuncture somehow was able to change the receptor binding ability, maybe through increasing receptor number. So, that one I think has gotten the most press.
I’ve also been involved in clinical trial that I mentioned earlier that I was the research assistant of. That one has actually gotten some nice press as well over the years. And we basically showed that it didn’t really seem to matter whether the needles were stimulated manually or if they were in the correct location. There seemed to be a nice analgesic response in fibromyalgia patients.
I’ve also done a study looking at proton spectroscopy showing that when acupuncture changes glutamate levels in the brain, clinical pain, experimental pain also changes as well and there’s a nice correlation, they track level each other.
You performed different mechanisms between real acupuncture and sham acupuncture. But recently, published many clinical trials failed to show differences between real acupuncture and sham acupuncture. What do you think of the meaning of these lines of the studies are, and the suggestion to overcome this kind of problem?
A couple of things. We now know that acupuncture for chronic pain does have a specific effect if the needles are put in the correct acupuncture point locations. But that effect is quite small. If you look at acupuncture trials for knee osteoarthritis or chronic low back pain, both acupuncture and sham acupuncture reduce pain significantly, the added benefit of correct needle placement, gains you only about the effect size of .15, which is a small effect size. But, it’s significantly, statically significantly different. So, I wouldn’t say that there’s no difference clinically, there is a difference clinically. But it’s just kind of small. You have to treat a lot of patients to really see that effect.
One thing I think we might be able to do better is, a lot of times in chronic pain studies, the patients themselves are very heterogeneous. So, we don’t really understand the different pathways for development of chronic pain. For example, in fibromyalgia, there could be a whole number of different problems in the patients that might cause them to chronic widespread pain. But they don’t all have the same pathology. And so, we’re learning that now that there’s actually subgroups of pain patients even under the umbrella of like fibromyalgia or chronic low back pain or knee osteoarthritis. They’re mixed. So, I think one thing we could do in acupuncture studies, is if we have more homogeneous or more controlled population that goes into the study, that reduces the variability and increases our likelihood of detecting a difference between verum and sham acupuncture. That’s one potential way that we might be able to improve efficacy studies. Clinical trials looking for efficacy for acupuncture.
Another way may be to look at quantitative sensory testing and use quantitative sensory testing, this ability to determine how sensitive someone is to an experimental pain stimulus and use that to predict responsiveness. We did a study that was published last year, where we looked at the fibromyalgia patients and we squeezed their thumbs with a pressure device. We found the patients that were not very tender didn’t respond to sham acupuncture very well at all. But they responded to verum acupuncture quite well. So, if you actually stratify the population to like, not so tender people versus very tender people, if you just looked at the non-tender people, you would’ve had a significant difference between verum and sham. Because for some reason, the fibromyalgia patients that are not sensitive to stimuli, don’t get an analgesic benefit from sham. So again, that’s kind of getting at that subgroup kind of thing, uh… kind of hypothesis.
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