Niacin and Mitochondrial Myopathy

Niacin is an organic compound and a form of vitamin B3, an essential human nutrient. It occurs naturally in many foods, including:

• Greens
• Meat
• Poultry
• Fish
• Eggs

Although in a fraction of the dose shown to achieve changes in cholesterol, many products are also fortified with niacin during manufacturing.

An international team of scientists, led by the University of Helsinki, have found that vitamin B3 or niacin delayed disease progression in patients with mitochondrial myopathy. Mitochondrial myopathy is a progressive disease with no previous curative treatments.

Researchers found in the study that mitochondrial myopathy patients have NAD+ deficiency in muscle and blood, and niacin is an efficient NAD+ booster in humans. Further, niacin improves muscle strength and fatty liver in mitochondrial myopathy. It boosts muscle mitochondrial biogenesis and respiratory chain activity in humans.

The study has been published in the journal Cell Metabolism.

Vitamin B3 forms have recently emerged as potent boosters of energy metabolism in rodents. These vitamins are precursors for NAD+, a molecular switch of metabolism between fasting and growth modes.

As fasting has been shown to promote health and longevity in, for example, mice, a variety of "NAD boosters" are being developed. However, whether actual NAD+ deficiency exists in human disease, and whether NAD+ boosters could have curative effects in patients with degenerative diseases, has remained elusive.

In the current publication, a collaborative team of investigators led by academy professor Anu Suomalainen-Wartiovaara and academy research fellow Eija Pirinen report lowered NAD+ levels in both blood and muscle of mitochondrial myopathy patients.

"The disease is characterized by progressive muscle weakness, exercise intolerance, and cramps. Currently, no treatments that would slow down disease progression exist," says Suomalainen-Wartiovaara.

Niacin - A Promising Treatment Option

Pirinen and colleagues report that niacin treatment efficiently increased blood NAD+ both in patients and healthy subjects. Niacin restored NAD+ in the muscle of the patients to the normal level and improved the strength of large muscles and mitochondrial oxidative capacity. Overall metabolism shifted towards that of normal subjects.

The results of this open pilot study revealed that niacin is a promising treatment option for mitochondrial myopathy. The authors emphasize, however, that niacin and NAD+ are efficient metabolic modifiers and niacin treatment should be cautiously applied only when NAD deficiency is detected, for example, in the patient's blood.

"Our results are a proof-of-principle that NAD+ deficiency exists in humans and that NAD+ boosters can delay progression of mitochondrial muscle disease," Suomalainen-Wartiovaara comments.

"The study is a significant leap in the development of targeted therapy options for energy metabolic diseases," Suomalainen-Wartiovaara continues.

For further reference log on to: http://dx.doi.org/10.1016/j.cmet.2020.04.008