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Scientists investigating potential link between toxic cyanobacteria and ALS

  • Dartmouth ALS doctor and researcher Elijah Stommel sits in his office at Dartmouth–Hitchcock Medical Center in Lebanon, on April 7, 2016. (ELIZABETH FRANTZ / Monitor staff)

  • Dartmouth ALS doctor and researcher Elijah Stommel sits in his office at Dartmouth–Hitchcock Medical Center in Lebanon, on April 7, 2016. (ELIZABETH FRANTZ / Monitor staff)

  • Dartmouth ALS doctor and researcher Elijah Stommel has been looking at environmental factors for the disease.

  • Mascoma Lake in Enfield is seen on a rainy day, April 7, 2016. (ELIZABETH FRANTZ / Monitor staff)

  • Mascoma Lake in Enfield is seen on a rainy day. A neurotoxin called BMAA, found in algae blooms on the lake, is being studied. ELIZABETH FRANTZ / Monitor staff

  • Dr. Elijah Stommel, right, and his colleagues Dr. Tracie Caller and Nicholas Field, fourth-year medical student at the University of Vermont, are studying the link between blue-green algae and Lou Gehrig's disease. October 2011. (courtesy photo by Jon Gilbert Fox)



Monitor staff
Sunday, April 17, 2016

Years ago, Dartmouth ALS doctor and researcher Elijah Stommel started noticing an unusual pattern around some of New Hampshire’s lakes and ponds.

Interviewing ALS patients at the Dartmouth-Hitchcock Medical Center in Lebanon, Stommel started seeing a common thread between patients; several lived along the shores of Mascoma Lake in nearby Enfield.

“We determined there might be about a 40-fold increase in ALS incidents in that area,” Stommel said. He started wondering if there was something in the lake that was linked to the high number of cases.

ALS is a mysterious neurological disease with no established causes, but a number of researchers across the country are studying whether environmental factors could play a part in triggering the disease. It’s estimated that 30,000 people in the U.S. have ALS, and 5,000 people a year die from the incurable disease.

Specifically, researchers are studying a potential link between ALS and a neurotoxin called BMAA, found in algae blooms like the ones that appear on Mascoma Lake in summer and early fall.

And Stommel has found that Mascoma Lake isn’t an outlier.

“We’re finding a clustering of ALS around lakes that have cyanobacterial blooms in the summertime,” Stommel said.

The largest cluster so far documented is around Mascoma Lake, but scientists have recorded smaller clusters in northern Vermont around Lake Champlain as well as one in the Bangor, Maine, area.

The body of research on environmental factors and neurological disease is growing, but is still a small subset of studies. In the past few years, “environmental causes were not and have not been the major focus,” said ethnobotanist and ALS researcher Paul Cox, director of the Institute of Ethnomedicine in Jackson Hole, Wyo. “We’re one of the first groups to argue that environments . . . pull the trigger.”

Cox says that while scientists haven’t been able to prove a definitive link between BMAA and ALS and other neurological diseases, “we have some pretty interesting data to (show) that’s possible.”

But one New England-based environmental law firm isn’t waiting. The Conservation Law Foundation recently sued the United State Environmental Protection Agency in an effort to clean up the Charles River in Boston, citing Cox and Stommel’s research.

Researchers readily admit there’s much to learn about a potential link. Added to that, scientist believe there’s no hard and fast rule to who gets ALS and who doesn’t. In other words, a lot of things have to fall into place for a diagnosis, including a possible genetic predisposition and exposure to other risk factors, which scientists are exploring.

“This is still a very rare disease,” Cox said. “It’s like, smoking doesn’t mean you get cancer, it just increases your risk.”

Inside cyanobacteria

In summer months, it’s not unusual to see a layer of blue-green scum floating gently on the surface of New Hampshire’s lakes and ponds.

“It will look like stuff you wouldn’t want to touch; it has a film near the surface,” said University of New Hampshire biologist Jim Haney.

The thin layer of goo can be made up of different types of cyanobacteria. The blooms are generally regarded as a nuisance, prompting warnings from the New Hampshire Department of Environmental Services at public beaches. Certain strains of cyanobacteria can cause other health problems, and swimming and other recreation can be prohibited in the summer months when conditions are at their worst.

In 2000, Haney first did a survey of 50 lakes and ponds in the state to see how many had cyanobacteria. He started thinking that some would and others would be without, but he found cyanobacteria were much more ubiquitous than he originally thought.

“We found in fact all the lakes had these toxins present, it was just a matter of how much was there,” Haney said.

Typically fed by nutrients in fertilizers, cyanobacteria are common in lakes and ponds in New Hampshire and other New England states. While New Hampshire scientists have determined all of the lakes and ponds in the state contain some level of cyanobacteria, they don’t know exactly how many of those blooms contain BMAA. Testing found BMAA in Mascoma Lake’s blooms, but many more lakes need to be analyzed.

It’s an area of ongoing research for Stommel and Haney. They’re trying to find out how people ingest BMAA, whether through breathing in aerosols around the lake, drinking water or eating fish.

Cyanobacteria blooms are not a New England-specific problem. The ancient microorganisms can be found all over the world, from Middle Eastern deserts to the Antarctic.

“They’re ubiquitous, they’re everywhere,” Stommel said.

Cyanobacteria feed off nutrients such as phosphorus and nitrogen, which come from erosion and runoff from agriculture, heavy industry and sewage. At the same time, the blooms suck oxygen out of the water, creating dead zones for fish and plants.

The shores of Lake Erie bordering Ohio have experienced some of the largest blooms, coming from phosphorus runoff in agriculture. Lake Champlain in Vermont has large blooms, which experts attribute to runoff from the state’s dairy industry as well as record phosphorus runoff in 2011, caused by erosion from Hurricane Irene’s flooding of streams and rivers.

But smaller blooms can come from something as simple as runoff containing household fertilizer people use to green up their lawns.

“It doesn’t take much, that’s the whole problem,” Haney said. “We’re choking our lakes from phosphorus from our own activities.”

This summer, Stommel and Haney will look at more freshwater ponds and lakes in New England, looking at BMAA levels and flying a blimp to try to detect whether the toxin is in the air around ponds.

Ethnobotanist Paul Cox says there’s no reason for panic, as ALS is still an extremely rare disease. In fact, he’s fielded calls from anxious Lake Mascoma homeowners, wondering if they should sell their lakefront property.

Possible link to ALS

Cox likens his work on ALS to “staring into the abyss” at times.

Cox’s area of expertise is trying to develop effective drugs to treat disease. The researcher, who previously researched the HIV/AIDs epidemic in the 1980s, found himself drawn to ALS, a disease he said had the same sense of despair and hopelessness at finding a cure. He has been studying the possible link between the BMAA toxin and neurological diseases since the 1990s.

One piece of the puzzle Cox studied started in remote villages in the Pacific Island of Guam, where observers noticed people were coming down with neurological diseases at astonishingly high rates. In some villages, about 25 percent of the adults were dying from a disease that sometimes presented symptoms including that of ALS, Alzheimer’s and Parkinson’s. Some adults had symptoms of all three diseases.

“It hit hardest in traditional villages,” Cox said.

Lab studies of the brains of Chamorro villagers who died showed high levels of the neurotoxin BMAA.

Cox decided that rather than spending his days in a laboratory, he wanted to go directly to the outbreak’s epicenter. So he flew to Guam and started interviewing villagers.

“We were very interested in diet,” he said. “I thought the Guam disease could be the Rosetta Stone.”

Cox and his team of researchers found BMAA was getting into the Chamorro diet in two ways. The neurotoxin was found in cyanobacteria naturally produced in the roots of the cycad tree, which grows on the island.

Islanders were consuming the cycads in one of two ways; first, they ground up cycad seeds into flour. Second, and somewhat more significantly, villagers hunted and ate large fruit bats called flying foxes, which themselves feasted on cycad seeds.

Researchers found high levels of BMAA in the flying foxes, which could have been ingested by the natives when they ate the animals. They also found high levels of BMAA in the brains of deceased villagers.

“Here we’re discovering the most culturally salient food item is triggering” the disease, Cox said.

More studies by Cox and his team of researchers followed, including one whose findings were published in January. That study looked at Vervet monkeys fed doses of BMAA, all of which developed tangled proteins and amyloid plaques in their brains.

Tangled proteins and amyloid plaques are hallmarks of both of Alzheimer’s disease and the paralytic, ALS-like disease experienced by the Guam villagers. As researchers examined brain scans of the monkeys, Cox remarked that the brains looked just like the ones of Alzheimer’s patients.

Cox didn’t know what to expect with the research, but the results threw him for a loop.

“It was just stunning, totally unexpected,” he said.

Cox said he thinks the evidence is strong that BMAA consumption produces tangled and misfolded proteins, and he’s also optimistic he and a team of researchers may have found something that can stop the process.

For a few years now, he’s been focused on something called L-Serine, an amino acid that also occurs naturally in foods such as soybeans, eggs and lentils. Cox’s vervet monkey study showed that when the BMAA monkeys were also fed doses of L-Serine, the density of the protein tangles was reduced by up to 85 percent and the disease’s progression slowed.

L-serine is promising in a number of ways, Cox said. It’s cheap and relatively safe to give to humans. A future L-serine clinical trial is slated to happen at Dartmouth-Hitchcock.

Other researchers have called Cox’s findings into question over the years, after finding different results with BMAA using different research methods. Cox himself has repeated his studies numerous times, “trying to find ways to disprove it.” But the results have remained constant, and he believes the work is sound.

He readily admits there’s a lot still unknown about ALS, but he remains hopeful he’s happened upon one risk factor for the disease.

CLF lawsuit against EPA

Cox and Stommel’s findings been enough to prompt the Conservation Law Foundation to sue the U.S. Environmental Protection Agency.

The law firm says the EPA isn’t implementing its own mandatory stormwater pollution standards, allowing phosphorus-rich stormwater runoff from parking lots and dripping off roofs of academic and hospital campuses.

“We’re really ramping up as we’d heard more about Dr. Cox and his colleagues,” said Conservation Law Foundation lawyer Chris Kilian. “It’s our belief that not only should regulators be paying attention to this emerging link, but they should be prioritizing and taking action now.”

Kilian has been following the research on BMAA for the past 10 years.

“We’ve been cautious and waiting for development and enhancement with the research where we felt more comfortable taking action on it,” he said.

Kilian said he’s not confident businesses will take it upon themselves to do the expensive work to prevent runoff. He said it falls upon the government to enforce regulations on stormwater instead.

And he doesn’t want to wait until the burden of scientific proof from researchers like Cox, Haney and Stommel has been more firmly established.

“We don’t want to wait 20 and 30 years and find out the entire time we’ve been exposing an entire generation to a toxin,” he said. “We know what we need to do to stop it.”