How did this ancient iceman spur an important Lyme disease discovery?
Named after the Ötzal Alps where he was discovered, Ötzi was just 45 when he died around 3,300 BCE. And though the oldest known European mummy didn’t die from complications of the disease, mitochondrial DNA analysis has shown that the bacteria responsible for Lyme disease resided deep in Ötzi’s bones. But had he survived, work from a team of scientists at the University of Toronto’s Faculty of Dentistry suggests that the 5,000 year old man might have suffered from bone loss as a result of his infection.
The ancient man’s infection was enough of a clue that a team of scientists from the University of Toronto set out to hunt for the mysterious Borrelia burgdorferi bacteria that cause Lyme disease in modern subjects. For, while scientists have long established a link between advanced Lyme disease and the development of osteoarthritis, until now no one has systematically studied the effects of this disease on bones.
“Bone pain has been reported since Lyme disease has been studied, but it’s not something that has been investigated.” explained Tara Moriarty, Assistant Professor at the Faculty of Dentistry and senior author of the study, published in the journal Infection and Immunity (IAI) late last month.
The bacteria were not only detectable in the bones of mice, they were seen to cause significant bone loss in the longer bones mere weeks after infection.
In fact, the bone loss developed at a rapid rate, taking just four weeks to advance to osteopenia, a forerunner to the more severe form of bone loss disease, osteoporosis — and the amount of bone loss directly correlated to the bacterial load found in the bones. The more bacteria present, the greater the rate of bone loss.
The findings suggests that monitoring bone loss in human Lyme disease patients may be warranted, especially because bone loss is a significant risk factor for fractures later in life. At the same time, the study raises new questions about the mysterious disease and its debilitating effects.
“One of our main focuses right now is on the mechanism that induces the bone loss,” said first author and recently graduated MSc student at the University of Toronto’s Faculty of Dentistry, Tian Cornelia Tang. Cellular studies are currently underway to determine just how the bacteria interact with the bone building cells of the body, osteoblasts, with the hope of finding new drug targets to combat not just the bacteria, but the newly discovered associated bone loss.
“We need to know how long the osteopenia lasts after bacterial infection, and whether it progresses to osteoporosis,” added Moriarty.
Although the fate of the ancient Ötzi may be fixed forever in time, his infection could soon aid thousands of people infected each year evade the devastating complications of Lyme disease.
Images: (TOP) Courtesy: Reconstruction of Ötzi the Iceman in the South Tyrol Museum of Archaeology © South Tyrol Museum of Archaeology/Kennis/A.Ochsenreiter. (http://www.iceman.it/en/25-years-of-oetzi-the-iceman-the-events/)
Otzi's hand: EURAC - Marion Lafogler