VA researchers study effects of smoking on therapeutic stem cells

Many in the research community believe there is huge potential for stem cell therapy to treat a broad range of diseases. Stem cells, special human cells that can develop into many different cell types, essentially serve as a repair system for the body.

Currently, more than 5,000 clinical trials worldwide are based on therapeutic stem cells, including some at VA hospitals for illnesses ranging from cardiovascular disease to cancer.

But gaps remain in the transition of stem cell application from the research stage to patients.

“One of these gaps is how a patient’s lifestyle choices and underlying health conditions may negatively affect stem cell therapy,” says Dr. Ngan Huang, a biomedical engineer at the VA Palo Alto Health Care System in California. “Given the prevalence of cigarette use and rise of electronic cigarettes, we believe this subject is an important aspect of stem cell application that remains unexplored. Not much is known about nicotine and its direct effect on therapeutic stem cells.”

Researchers to treat disease that obstructs blood vessels

Huang and Dr. Alex Chan, a postdoctoral research fellow at VA Palo Alto, are studying the effects of nicotine, a highly addictive tobacco stimulant normally inhaled with cigarettes, on therapeutic stem cells. The two co-authored a review article on the effects of nicotine on stem cell therapy that appeared online earlier this year in the journal Regenerative Medicine.

There are two arms to their study. In one, Huang and Chan are injecting cells into mice that have been exposed to nicotine, as well as those that haven’t, with the intention of treating peripheral artery disease, which obstructs blood vessels in the arms and legs. In the other arm, the researchers will compare stem cells in smokers and non-smokers. They will see if the groups differ at producing cells that are effective at making new blood vessels.

Veterans more likely to use tobacco products than non-Veterans

Veterans and service members are more likely to use tobacco products than civilians, according to the U.S. Centers for Disease Control and Prevention (CDC). CDC statistics show that about 30% of Veterans used some form of a tobacco from 2010 to 2015. Tobacco use was higher among Veterans than non-Veterans for males and females across all age groups, except men ages 50 and older.

Huang and Chan are hoping to bring more awareness about the effects of smoking on stem cells to the Veteran community, as well as other types of nicotine exposure that may impact the effectiveness of stem cell therapy, such as electronic cigarettes. E-cigarettes, also known as “vapes,” are battery-operated devices that people use to inhale an aerosol, which typically contains nicotine, flavorings, and other chemicals that are known to harm one’s respiratory system.

The `gold standard treatment’

The effects of lifestyle and co-occurring health conditions on stem cells have been “largely neglected,” Chan explains. “Preclinical studies of stem cell therapies have mainly been conducted in healthy animal models. This does not reflect the settings in the clinics where patients requiring stem cell therapy may have underlying diseases, such as diabetes, high blood pressure, and lifestyle choices like smoking and diet.”

The overall results from the study, Huang notes, may prompt researchers to take nicotine or tobacco exposure into consideration in clinical trials. As more trials take place for stem cell therapies in many applications, she says, the field will trend toward more effective therapies.

“But with many unknowns, it will be years before stem cells therapies become the gold standard treatment for certain diseases,” she says.

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