Specialized Pro-resolving Mediators (SPMs)

The bottom line

Fish oil is the darling of the nutrition world, but the next step for pain might be focusing on SPMs (“Specialized Pro-resolving Mediators”) extracted from fish oil. Studies are scarce, but promising.

A little primer on inflammation and pain

When you sprain your ankle, you experience inflammation. When you don’t eat well or exercise, your heart and liver can experience inflammation. In fact, inflammation is involved in a mind-boggling number of diseases. But inflammation is also key to healing. So when does “appropriate” inflammation turn into “inappropriate” inflammation ? Well…that’s a tough question, and one that scientists are actively exploring. Let’s take just a brief look at what happens when the inflammatory reaction goes haywire, and we experience chronic pain.

Chronic pain generally means pain lasting greater than 3-6 months . Is inflammation happening that whole time? Well…it depends. In short term pain, like a mild sprained ankle, inflammation does its job very efficiently. That job involves clearing away damaged cells, initiating the healing process, and then making a graceful exit. But what if, for some reason, inflammation does not want to make a graceful exit? What if it wants to stay forever? Then you can get something like Complex Regional Pain Syndrome (CRPS), one of the top suckiest pain conditions.

What are SPMs?

It’s possible that SPMs could blow existing prescription pain-relievers out the water in the near future. Many prescription and over-the-counter pills interrupt the pathway that produces inflammatory compounds called prostaglandins. Prostaglandins are also important for protecting stomach and intestine lining though, so some pills of this type can cause ulcers and other bad tummy issues. Newer pills like Vioxx and Celebrex are better at avoiding such damage, but they sometimes cause heart damage instead. Bummer.

So what if you’ve got pain and are (rightly) wary of popping too many pills? Enter … SPMs. Other than side effects, one downside of drugs is that they might not be so great at clearing inflammatory factors that hang around for along time (chronic pain) as opposed to acute inflammation after an injury (acute pain). SPMs were discovered back in 2000 by Harvard scientists, and were named for their ability to resolve inflammation (apparently these scientists were in a rush and couldn’t think of a more creative name?). SPMs are actually made out of certain prostaglandins by the body, which are themselves derived from omega-3 fats, and this process can be sped up by some things such as aspirin. Along with other chemicals, resolvins decrease pain by blocking the action of certain troublesome immune cells that are called into the painful area while calling in other immune cells to clear dead tissue that can increase pain levels.

Could SPMs be used as a pain therapy?

What makes SPMs more promising than drugs? Well for one, resolvins allow acute inflammation to happen, which is important for healing, while preventing chronic inflammation. Second, compared to anti-inflammatory drugs or opioid painkillers, lab studies have shown that a much much smaller amount of resolvins are needed to stop pain. They are INCREDIBLY powerful. Third and perhaps most importantly, resolvins seem to improve chronic pain that is caused by sensitization of nerves . In other words, resolvins could reduce your nervous system’s “pain memory”.

But SPMs aren’t a slam dunk…at least not yet. Some of the studies were done by injecting the spinal cords of rats. Rats studies don’t always translate well into humans — humans are unique in the complexity of their pain reactions. And people with pain conditions don’t take well to excruciating spinal injections. However, there have been preliminary studies of normal non-spinal injections.

Does any of this mean anything practical?

Why…yes! The name of the game for reducing chronic pain is desensitizing your nerves, nourishing your body, and normalizing posture and motion. Resolvins are derived from omega-3s, so this underscores the importance of eating fatty fish and reducing consumption of competing omega-6 fatty acids found in vegetable oils . However, it isn’t known if regular fish consumption produces enough resolvins to overcome pain conditions, and fish oil supplementation doesn’t always perform so well in pain trials, so hopefully research will continue into developing practical resolvin treatments. Because they reduce inflammation so well, SPMs show promise for conditions such as rheumatoid arthritis, in which disease-modifying drugs (DMARDs) are use to slow down disease progression.