Vitamin B3 Shows Promise in Treating Chronic Inflammatory Pain

A type of vitamin B3 called nicotinamide riboside reduces persistent pain in mice, suggesting it may also treat chronic pain in humans.

Inflammation (the body’s first line of defense against injury and pathogens) is a major cause of pain. However, some people experience continued pain even after the inflammation has subsided.

To understand why, Niels Eichelkamp and colleagues from Utrecht University in the Netherlands analyzed the effects of inflammation on mitochondria, the powerhouses of cells. Previous research has linked chronic pain to mitochondrial dysfunction, particularly in specialized nerve cells called sensory neurons that sense changes in the environment.

The researchers injected a substance that causes inflammation into the hind legs of 15 mice. They then measured the amount of oxygen consumed by the mitochondria in the animals’ sensory neurons, which indicates mitochondrial function. They found that a week after the inflammation had subsided, the mitochondria were consuming significantly more oxygen than before the injection, suggesting that the inflammation caused lasting changes in their function. Further experiments linked these mitochondrial changes to increased pain sensitivity in the rodents even after inflammation had subsided.

The researchers then analyzed molecular byproducts of chemical reactions called metabolites in the animals’ mitochondria. They compared these to mitochondrial metabolites in naive mice. caused inflammation. The researchers found that levels of nicotinamide riboside in the mitochondria of the mice’s sensory neurons were lower than expected after the inflammation subsided. This is a type of vitamin B3 that is important for mitochondrial function.

So, about a week after inducing inflammation in another group of 12 mice, Eichelkamp and his team gave half of them a high dose of nicotinamide riboside (500 milligrams per kilogram of body weight). administered. In comparison, her recommended daily amount of vitamin B3 for most adults is 14 milligrams and 16 milligrams. They then assessed the animals’ sensitivity to pain by measuring how quickly they removed their paws from the heat. Mice that did not receive nicotinamide riboside withdrew their paws twice as fast on average as those that did, suggesting that the supplement reduced pain.

Taken together, these findings reveal two things. One is that inflammation can impair mitochondrial function in sensory neurons, and these dysfunctions increase the risk of chronic pain even after inflammation has subsided. Second, taking nicotinamide riboside supplements may help treat this chronic pain by restoring mitochondrial function.

However, people with chronic pain should not rush to take these supplements. “[This research] Still inside the rodent. How does that translate to humans? We need to check that first,” Eikelkamp said. In clinical trials, nicotinamide riboside may be ineffective or have unintended consequences, he says.

Even if these findings apply to humans, they probably only apply to certain types of chronic pain, such as chronic inflammatory diseases, Eikelkamp says. For example, more than 20 percent A proportion of patients with rheumatoid arthritis, a chronic disease characterized by persistent joint inflammation, continue to experience pain even when inflammation levels are low. Therefore, it makes sense to test these findings in that demographic first.