Could Nicotine Be Used to Treat MS Someday?
We know that cigarette smoking is bad for our health. The Centers for Disease Control and Prevention (CDC) states that more than 16 million Americans suffer from a disease caused by smoking, such as cancer, heart disease, stroke, lung diseases, or diabetes. In the United States, cigarette smoking is responsible for more than 480,000 deaths per year, including an estimated 41,000 deaths in persons exposed to secondhand smoke. Worldwide, tobacco use kills more than 5 million people annually with numbers growing each year.
Epidemiological studies have reported that cigarette smoking increases the risk of developing multiple sclerosis and accelerates disease progression (Sundstrom, 2008). A recent study demonstrated that in a large population of MS patients in England, current smoking behavior was associated with more than 2.5-fold increased risk of death. In addition, the life expectancy of current smokers with MS was reduced by about 10 years as compared to non-smokers with MS (Manouchehrinia, 2014).
It is logical that smokers who understand the increased risk of tobacco would want to do what they can to limit their exposure to nicotine or other harmful chemicals while smoking. Hence the tobacco industry has developed "reduced exposure" or "light" products containing lower levels of nicotine, nitrosamines, or other chemicals deemed to be potentially toxic. However, these ultralow nicotine or tobacco-free cigarettes may be worse than their full flavor versions.
Researchers comparing the effects of exposure to full flavor, nicotine-free, or ultralow nicotine products on the integrity of the blood-brain-barrier (BBB) found that nicotine-free and ultralow nicotine cigarettes are potentially more harmful to the BBB endothelium than regular tobacco products. This study demonstrates that the detrimental effect of tobacco smoke on the BBB is strongly correlated to the tar and nitric oxide levels in the cigarettes rather than the nicotine content (Naik, 2014).
Meanwhile, a different team of researchers have assessed the effects of nicotine and non-nicotine components of cigarette smoke on experimental autoimmune encephalomyelitis (EAE), a form of MS induced in mice. They found that nicotine significantly improved the severity of EAE, as shown by reduced demyelination, increased body weight, and attenuated microglial activation. Nicotine administration after the development of EAE symptoms prevented further disease exacerbation, suggesting that it might be useful as an EAE/MS therapeutic agent (Gao, 2014).
In contrast, exposure to non-nicotine components of cigarette smoke accelerated and increased clinical symptoms and disease severity at early stages of the disease. This was consistent with results from previous epidemiological studies showing that MS progressed faster in patients who smoked. Results from this study suggest that the non-nicotine components of cigarette smoke, such as acrolein, could be responsible for the detrimental effects of smoking on MS, whereas nicotine may provide some benefit.
Authors state that this is the first study to provide evidence to support the proposed role of nicotine as a therapy for on-going MS, however, they caution that more research is needed. Although nicotine suppressed pro-inflammatory action of T cells and reduced symptoms of EAE/MS, it has been associated with inflammation in the respiratory system and cancer. The potential side effects of nicotine patches will need to be evaluated carefully.
So please talk to your doctor before you are tempted to go out and purchase nicotine patches in an attempt to slow down your MS. And certainly, don't suddenly take up cigarette smoking as it has been tied to increased disease and premature death in people with or without MS.
Smoking and Tobacco Use [Fact Sheet]. Center of Disease Control and Prevention. Accessed October 24, 2014 at http://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/
Gao Z, Nissen JC, Ji K, Tsirka SE. The Experimental Autoimmune Encephalomyelitis Disease Course Is Modulated by Nicotine and Other Cigarette Smoke Components. PLoS One. 2014 Sep 24;9(9):e107979. doi: 10.1371/journal.pone.0107979. eCollection 2014.
Manouchehrinia A, Weston M, Tench CR, Britton J, Constantinescu CS. Tobacco smoking and excess mortality in multiple sclerosis: a cohort study. J Neurol Neurosurg Psychiatry. 2014 Oct;85(10):1091-5. doi: 10.1136/jnnp-2013-307187. Epub 2014 Feb 25.
Naik P, Fofaria N, Prasad S, et al. Oxidative and pro-inflammatory impact of regular and denicotinized cigarettes on blood brain barrier endothelial cells: is smoking reduced or nicotine-free products really safe? BMC Neurosci. 2014 Apr 23;15:51. doi: 10.1186/1471-2202-15-51.
Sundstrom P, Nystrom L. Smoking worsens the prognosis in multiple sclerosis. Mult Scler. 2008;14:1031-35.