Faculty Spotlight: Matthew Springer, PhD
Dr. Matthew Springer, an expert in the effects of secondhand smoke, was at Paul McCartney’s concert in AT&T Park in 2010 when a cloud of smoke wafted over the audience.
He was surprised, because people generally refrain from smoking in public spaces like the ballpark. Then Dr. Springer realized it was marijuana. "Paul McCartney stopped between songs and said, ‘There’s something in the air – it must be San Francisco,’" he recalled with a laugh.
Dr. Springer, who holds a PhD in biological sciences and has been on the UCSF faculty since 2003, realized that people who avoid tobacco smoke may think that marijuana secondhand smoke is natural or medicinal, and therefore harmless. But there is actually very little research about the health effects of marijuana secondhand smoke.
Spurred by a desire to help policymakers and the public make informed decisions as marijuana becomes legal in more communities, Dr. Springer began a new avenue of investigation. Using the same techniques that he has used to study secondhand tobacco smoke, his lab found that rats that are exposed to secondhand marijuana smoke for one minute experience a substantial decrease in the ability of blood vessels to expand and carry more blood. This ability, called flow-mediated vasodilation (FMD), is important – for example, it allows someone who is exercising to send more oxygen to their muscles.
It has been known for many years that FMD is impaired by smoking tobacco. Several research groups, including some at UCSF, have shown that humans exposed to 30 minutes of secondhand tobacco smoke have temporarily impaired FMD. After a couple of hours, their blood vessels recover. However, people who are frequently exposed to tobacco secondhand smoke, such as family members of smokers, have the blood vessels of smokers: repeated exposure to secondhand smoke produces a long-term effect.
In a paper recently published in the Journal of the American Heart Association, Dr. Springer’s latest research found that rats exposed to as little as one minute of secondhand smoke – whether it was from tobacco or marijuana – experienced FMD impairment. Interestingly, while the rats’ blood vessels recovered within 30 minutes of exposure to tobacco secondhand smoke, the impairment lasted at least 90 minutes after they had been exposed to marijuana secondhand smoke. "This is way worse than what we see with tobacco [secondhand smoke]," said Dr. Springer. "That was pretty astounding, and we said, ‘People need to know about this.’"
Informing the Public Debate
As a pioneer in the study of how marijuana secondhand smoke affects cardiovascular function, Dr. Springer has taken the initiative to share his discoveries with policymakers who are deciding how to regulate marijuana use in public spaces. So far, he has provided information about his findings to aides to the San Francisco Board of Supervisors, Alameda County Board of Supervisors, and Burlingame City Council, as well as the Anchorage Assembly in Alaska, the mayor and council of Washington, DC, and the premier and associate health minister of Ontario, Canada. He has also published letters to the editor in the Washington Post, the Toronto Star, and the Denver Post, and sent a policy briefing to Lieutenant Governor Gavin Newsom's Blue Ribbon Commission on Marijuana Policy. Dr. Springer has also been interviewed on the topic by KCBS Radio, KGO Radio, Fox News and CBS News, among other media outlets.
Dr. Springer has set up an automated Google search for marijuana secondhand smoke to alert him to local debates on the topic. "Some people want to allow marijuana smoking in places where tobacco smoking is not allowed, and someone always brings up the statement, ‘There is no scientific evidence that marijuana smoke is harmful,’" he said. "Whenever we see that, we zip in and say, ‘Wait a minute, we’ve found some evidence that marijuana smoke is not necessarily harmless, so please rethink your basic premise.’"
Most recently, aides to California Assemblymember Jim Wood, D-Healdsburg, contacted Dr. Springer to obtain a statement regarding AB 2300, a medical marijuana bill that allows landlords to prohibit smoking of marijuana – even medical marijuana – in rental properties where tobacco smoking is banned. The bill is primarily aimed at the transfer of smoke from one home to another in multi-unit housing. AB 2300 passed the California Assembly 77-0 in May, passed the Senate Judiciary Committee 7-0 in June, and is scheduled to be voted on by the full Senate later this summer. "Our initially reported marijuana results were cited as one of the reasons that Assemblymember Wood wrote this bill," said Dr. Springer. "This is a good example of how this kind of work can influence public health policy."
Interestingly, Dr. Springer’s lab found that even in marijuana which had been treated to remove THC, or tetrahydrocannabinol – the compound which produces the "high" in users – the secondhand smoke produced the same adverse effects on blood vessels. "This is not a marijuana drug effect, this was a marijuana smoke effect," he said. "Which makes sense, because cigarette smoke does it, too."
Another important point is that most previous studies have investigated whether there is a link between marijuana secondhand smoke and lung cancer or lung function, with mixed results. Dr. Springer’s research focuses on cardiovascular function, demonstrating a clear-cut physiological effect in a rat model. "The vast majority of deaths caused by secondhand tobacco smoke are thought to be from cardiovascular disease, not lung cancer," he said. Finding a link between marijuana secondhand smoke and adverse cardiovascular effects is therefore something that merits attention and further study.
Dr. Springer said he intentionally remains agnostic on whether marijuana should be legalized. "I don’t want to come across as having a pro- or anti-legalization agenda," he said. "But if people are going to smoke marijuana and other people are exposed to that smoke, we have to look at that as if it were tobacco secondhand smoke."
He is also interested in studying whether multiple short exposures to marijuana can lead to long-term impairments, similar to the effects of tobacco secondhand smoke. Yet another interest is whether smoking marijuana using a vaporizer would allow people to avoid blood vessel impairment.
Challenges and Rewards
Conducting this research in marijuana posed more obstacles than his research on tobacco secondhand smoke. Marijuana is a Schedule 1 controlled substance, and using it for research required approvals from the US Drug Enforcement Agency (DEA), the US Food and Drug Administration (FDA), the State of California, and the UC police. Securing these approvals took about a year, which was a little ironic given that Dr. Springer’s Parnassus lab is a short walk from Haight Street and Golden Gate Park.
"I told the DEA agent, ‘You know, just down the hill is the place where you have to tell people, ‘I’m sorry, I don’t want to buy your marijuana,’" Dr. Springer recalled ruefully. "It was then that I found out that you really shouldn’t joke with DEA agents."
Despite the particular challenges of his investigations, Dr. Springer is excited to conduct research that could have such immediate applications. "As a non-clinician in a clinical division, it is great to be involved in something with a defined public health benefit," he said. "As cardiologists, my colleagues are curing patients or getting them to change their lifestyles. I love this [marijuana] project, because by demonstrating things that people don’t already know, if people change their behavior and avoid combustion products that could be causing them decreased health, we’ve actually had a direct effect on the health of individuals."
Improving Treatment for Heart Attacks
Dr. Springer’s lab and other research groups have shown that in rodent models, giving mice that survive a heart attack some cells derived from the bone marrow can help these at-risk heart cells to survive, thereby minimizing the extent of the scar tissue. He hypothesizes that this cell therapy works due to a paracrine effect –the implanted bone marrow cells produce yet-to-be identified factors that enhance the preservation of tissue.
However, attempts to use this approach in humans in clinical trials did not work as well as it did in rodents. Dr. Springer’s research found the likely reason why. The animals in typical rodent cell therapy experiments have been genetically identical, so researchers have harvested cells from young, healthy donor mice and implanted them into the mice which had suffered heart attacks. However, humans need to receive their own cells to avoid the risk of rejection by the immune system. Participants in the clinical trials received their own bone marrow cells that were harvested after they had a heart attack. "We think inflammation develops because of the heart attack, which changes the composition of the bone marrow," said Dr. Springer. "It’s different than if they were receiving bone marrow cells from young, healthy people."
His lab is currently trying to figure out ways to successfully use donor cells from older mice or those that have already undergone a heart attack, in the hopes that such an approach could also be used in humans."
Earthquakes and Music
In addition to having a broad range of scientific pursuits, Dr. Springer has an eclectic mix of other interests. He is passionate about earthquake preparedness, spawned in part by his own experience of several California temblors. His father was a physics professor at the University of Southern California, so Dr. Springer was in the Sylmar earthquake of 1971 as a child. In 1989, Dr. Springer was earning his PhD at Stanford during the Loma Prieta quake. He also grew up in Northridge; although he was living in the Bay Area by the time the 1994 Northridge earthquake struck, his family was greatly affected by it.
"I have learned from experience and have a decently well-arranged home for earthquake safety," said Dr. Springer. "Around 2007, I was thinking that we are recruiting people from other parts of the country and the world to work with us in our labs, and it would be nice to give them some hints on how to live in California. Just like if you’re in New York City, you probably tell new recruits not to go jogging in Central Park at two in the morning by themselves. I thought, I should at least warn people not to hang a heavy picture over their bed because we have earthquakes."
Dr. Springer made a presentation to his lab, and then to the Division of Cardiology. He now gives these earthquake safety lectures at several UCSF campuses as well as branches of the San Francisco Public Library – about 10 to 15 talks annually. He also writes the Quaketips blog, which receives about 6,000 page views each month, and has been interviewed several times by local media on earthquake preparedness.
"To me, a professor in a clinical division is not just someone who teaches people who come to him or her," said Dr. Springer. "Such a professor serves a role in public. If I can impact public health by educating people about precautions they can take to prevent them from being injured or perhaps killed in the next big earthquake, or perhaps by getting them to avoid marijuana secondhand smoke for that matter, then I can feel that the ‘Professor of Medicine’ title actually is valid."
Dr. Springer is also an avid musician. He plays the violin, piano, various percussion instruments, and erhu – the Chinese violin. He has played violin and percussion with the Peninsula Symphony Orchestra since 1999, and spends every Tuesday night in rehearsal.
"You’ve got to feed both halves of your brain or your soul," he said. "Science is cerebral, and music isn’t. There is a lot more feeling in the music that you just can’t do in science." About 15 years ago, he suffered from tendonitis and had to stop playing for about six months. "Without the music, life went from being in color to being in black and white," said Dr. Springer. "You go to work, you do the research, but there was a dimension that just wasn’t there. For other people it’s baseball or whatever, but this is my own personal necessity."
He also appreciates how playing an instrument can counterbalance the often glacial pace of scientific research. "In science, you can go for months without seeing any progress," said Dr. Springer. "Whereas when I sit down and practice my music, I’m better after practice. How cool is that?"
Finding a Niche
Dr. Springer said his career trajectory has shifted from pure basic science – his graduate work examined developmental gene regulation in a bread mold – to more applied or translational science. "I have only the utmost respect for people who do the pure basic research," he said. "I just needed, for my own satisfaction, to see a stronger link to helping people…. It’s good to find where you feel the most reward, and gravitate towards that."
His lab attracts trainees from around the world, including researchers from China and Iran; many are so motivated to work with him that they are willing to self-fund their positions, though Dr. Springer does try to help them secure fellowships.
"I will forever be grateful to the Cardiology Division for bringing me on," said Dr. Springer. "Being in a clinical division opened up possibilities that were not accessible to me when I was in a basic department. The level of moral support is very good here."
– Elizabeth Chur