When meeting meet Gregory S. Thomas, MD, MPH, FACC, you may not immediately suspect that he does field research with mummies: he dons neither a leather jacket nor a fedora, nor has a bullwhip holstered at the waist.

Yet, over the last 15 years, he has led an international team of cardiologists, historians, archeologists, anthropologists and radiologists in conducting CT scans of mummified peoples from around the world to understand their atherosclerotic disease burden.

The team's findings are astounding. Arterial calcification has been found in the remains of people worldwide, regardless of sex, age, diet, culture or geography. The latest results from their Global HORUS study, published in April in the European Heart Journal, are shaping our very understanding of how and why humans develop atherosclerosis.

Thomas was kind enough to speak with me about this revolutionary work. He is clinical professor of medicine, University of California, Irvine, and medical director emeritus, Long Beach Medical Center, as well as the founding president of The Paleocardiology Foundation.

Unexpected Inspiration

The inspiration for studying mummies came from a visit to Cairo, Egypt in 2008, during his leadership years with the American Society of Nuclear Cardiology. Thomas met with Adel Allam, MD, an Egyptian nuclear cardiologist, to tour his lab and compare clinical processes.

During the visit, they toured the Egyptian Museum of Antiquities. While in the museum's famous mummy room, which houses the remains of dozens of pharaohs, one caught his eye: Pharaoh Merneptah, who ruled around 1200 B.C.E.

The Pharaoh's golden sarcophagus was accompanied by a nameplate stating he died at age 60 of, among other things, arteriosclerosis. Thomas was struck: how could a person who lived in an age without cigarettes, processed foods, automobiles or abundant saturated fats have developed atherosclerosis? And how could they have diagnosed him?

Thomas and Allam conceived a plan to scan the mummy to look for calcifications, hypothesizing that the calcium in advanced atherosclerotic plaques may be visible on CT. They authored a proposal to the Supreme Council of the Antiquities of Egypt, which ultimately approved the work, provided that no royal mummies were included. Pharaoh Merneptah would keep his secrets.

A year later, after assembling an international research team, they scanned more than 20 of the Egyptian mummies in the museum. To their amazement, dense vascular calcium deposits were present in nearly half. Their conclusion unsettled prevailing theories about atherosclerosis: modern risk factors alone are not sufficient to explain the burden of arterial disease in humans.

The findings were a sensation with the lay press and in the academic community alike and spurred an even greater interest in studying people of the past to better understand disease in people of today.

To strengthen their findings, the team, now monikered HORUS, after the Egyptian god of the afterlife, sought more mummies. Thomas explains: Egyptian mummies were artificially embalmed and desiccated with salt for over 40 days, wrapped in linens, often with the internal organs intentionally preserved in jars.

In contrast, other cultures, particularly those in very hot or very cold dry climates, found they could mummify their dead ritualistically without embalming by placing them in a hole or cave to desiccate, a process called "natural mummification."

The HORUS team wondered whether the sophisticated Egyptian embalming technique may have promoted tissue calcification and sought out "natural mummies" for comparison. Their search led them to mummies from ancient cultures as diverse as those of Peru, the Four Corners region of North America, and Asia.

Despite a worldwide hunt across thousands of years, the HORUS team has not identified any culture whose mummified peoples are free of CT-detected arterial calcium. They even discovered disease in mummies who were as young as their twenties when they died.

Ever since the initial results, the HORUS project has expanded to include nearly 240 mummified peoples from cultures around the world. Atherosclerosis has been discovered in each of the studied cultures. The hunt for an ancient culture without any arterial disease continues.

One of Thomas' joys in the project has been working at the intersection of history, culture and cardiology. For example, both the Inuits of Greenland and the Aleutian Islanders of modern-day Alaska lived true hunter-gatherer lifestyles with similar maritime-based diets. Mummies from both cultures have vascular calcifications.

Working with the HORUS team, Thomas learned of a possible explanation. Both cultures wintered in smoky dwellings – Inuits in igloos and Aleutian Islanders in underground longhouses – which would have been filled with fumes from cooking fires for warmth and heat.

Secondhand smoke exposure may have caused inflammation. Perhaps inflammation has always been a driver of atherosclerosis. Perhaps what has changed over time are merely the sources of that inflammation.

Building A Career, A Community

Reflecting on his many adventures, Thomas offers some earned wisdom for young cardiologists. First, stay involved in the cardiology community and contribute to the field. Many treasured friendships developed during his enriching and impressive academic career. Second, many of the best ideas can be found at the intersection of seemingly disparate disciplines. Consider what untested perspective and outside expertise you might be able to bring to a vexing research problem. Third, start early. Young cardiologists sometimes do not realize how much they can power the field with their observations and energy. Fourth, stay curious. If he hadn't indulged in a visit to the Egyptian Museum, he might never have stumbled across the vaunted Pharaoh who inspired the HORUS project.

Finally, enjoy the ride. It's a privilege to practice medicine, and a single life can influence future generations – perhaps even 3,000 years in the future.

This article was authored by Robert Milford Tungate, MD, Chief Fellow, Cardiovascular Disease, at the University of California, Irvine, and member of the Fellows in Training Member Section.

Clinical Topics: Cardiovascular Care Team, Noninvasive Imaging, Computed Tomography, Nuclear Imaging

Keywords: Cardiology Magazine, ACC Publications, Mummies, Heart Diseases, Plaque, Atherosclerotic, Egypt, Egypt, Ancient, Tomography, X-Ray Computed