Thursday, January 21, 2016

A 5,300 Year Old Stomach Ache

In 1991, one of the best preserved mummies was found frozen in the Ötztal Alps, a mountain range near the border of Austria and Italy. This 5,300 year old man was named Ötzi and has been fascinating nosey scientists ever since. So far, scientists have learned about Neolithic fashions and dietary habits, and even identified his cause of death...solving one of the oldest “cold cases” in CSI history. (For the curious, poor Ötzi appears to have been attacked. He took a blow to the head and an arrow to his shoulder).

The well-preserved remains of the “iceman” named Ötzi.

Remarkably, genetic studies of folks living in Austria today reveal that Ötzi has some living relatives. Researchers found that at least 19 people may share a common ancestor with Ötzi, but the odds of one being a direct descendent of Ötzi himself are very remote. Some of these living relatives can be seen in a series of commercials for the auto insurance company Geico:


Ötzi provides a window into our past - a glimpse of what life might have been like 5,300 years ago. It turns out that Ötzi suffered from many of the same problems that we still have to contend with today. His body shows signs of heart disease, tooth decay, and joint pain, possibly caused by Borrelia borgdorferi, the bacteria that causes Lyme disease. The latest secret that scientists Frank Maixner and Albert Zink have coaxed out of Ötzi is that he was infected with another bacterial species that still causes grief in millions of people here and now:  Helicobacter pylori.

This is an artist’s rendition of Ötzi. But scientists didn’t just find a 5,300 year old human ancestor that day. They also found 5,300 year old bacteria.
Thanks to a landmark study in the 1980s, we now know that Helicobacter pylori is a causative agent of gastritis or stomach ulcers. Previously, doctors believed that stomach ulcers were simply caused by environmental factors - too much stress, spicy food, or smoking. But Drs. Barry Marshall and Robin Warren had a “gut feeling” that this model was wrong after they repeatedly found bacteria in the peptic ulcer biopsies from patients.

For decades, doctors believed that gastric ulcers were caused by stress. The idea that they were caused by a bacterial infection was a profound discovery and revolutionized treatment of this common ailment.
A lot of medical professionals had a hard time swallowing the idea that gastric ulcers were really an infection. Marshall and Warren faced great difficulty getting their results published in scientific journals. Many other doctors at the time mentioned how controlling the acid in the stomach usually helped patients feel better, and they balked at the idea that bacteria could survive in the acidic milieu of the stomach. Today, we now know that some bacteria can thrive in even the most inhospitable of places, including areas of high acidity. Helicobacter pylori is one such “acidophile” – it grows best under acidic conditions. This also explains why some ulcer patients recover after taking medication that reduces stomach acid; acid reducers cause a gastric climate change that is less favorable to the growth of Helicobacter pylori.

On June 12, 1984, Barry Marshall drank a culture of live Helicobacter pylori. He developed an ulcer, which he successfully treated with antibiotics. A tabloid newspaper first covered “the guinea-pig doctor” story, alongside stories of alien abductions and celebrity gossip. Ultimately, the stunt finally convinced the skeptics and won Marshall and Warren the Nobel Prize in Physiology or Medicine for 2005.
How do we get infected with Helicobacter pylori? The bacteria can be contracted through saliva or accidental ingestion of material coming out of the other end of a person. Somewhere along the way, a little poo from an infected person got into your food/water (or on your hands) and found its way into your gut. As gross as that sounds, it must happen a lot because Helicobacter pylori is present in the gut of billions of people. However, it causes ulcers in only 10% of them. 

Scientists don’t currently know why the bacteria attack the stomach lining of some people but not others. But if you are one of those unlucky few, the damage caused by the bacteria allows stomach acid to pass through the protective lining, which can cause bleeding and digestive problems, and obviously a lot of pain and discomfort.

But thanks to the renegade efforts of Barry Marshall, doctors now know how to treat gastric ulcers more effectively with a simple course of antibiotics. It is perhaps no surprise to you now that our old friend Ötzi had Helicobacter pylori in his tummy. The bug is very common and easily contracted, especially in his day when hand sanitizers were not easily accessible. Whether Ötzi’s Helicobacter pylori actually caused a gastric ulcer is hard to say, as his stomach lining was not preserved well enough to draw firm conclusions. One day we may find a specific type of genetic mutation in people prone to stomach ulcers, which would allow us to revisit the question.

If you want to learn more about the cracking of the stomach ulcer mystery, check out the following video.


Contributed by:  Bill Sullivan, Ph.D.

Follow Bill on Twitter.

Williams AC, Edwards HG, & Barry BW (1995). The 'Iceman': molecular structure of 5200-year-old skin characterised by Raman spectroscopy and electron microscopy. Biochimica et biophysica acta, 1246 (1), 98-105 PMID: 7811737

Tito RY, Knights D, Metcalf J, Obregon-Tito AJ, Cleeland L, Najar F, Roe B, Reinhard K, Sobolik K, Belknap S, Foster M, Spicer P, Knight R, & Lewis CM Jr (2012). Insights from characterizing extinct human gut microbiomes. PloS one, 7 (12) PMID: 23251439

Maixner, F., Krause-Kyora, B., Turaev, D., Herbig, A., Hoopmann, M., Hallows, J., Kusebauch, U., Vigl, E., Malfertheiner, P., Megraud, F., OSullivan, N., Cipollini, G., Coia, V., Samadelli, M., Engstrand, L., Linz, B., Moritz, R., Grimm, R., Krause, J., Nebel, A., Moodley, Y., Rattei, T., & Zink, A. (2016). The 5300-year-old Helicobacter pylori genome of the Iceman Science, 351 (6269), 162-165 DOI: 10.1126/science.aad2545

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