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Beatrix Dudzik (center), Ph.D., assistant professor of anatomy at Lincoln Memorial University's DeBusk College of Osteopathic Medicine, has been awarded a $377,535 grant from the U.S. Department of Justice Office of Justice Programs to conduct research on how to better determine postmortem intervals for skeletal remains. (Photo: Courtesy of Lincoln Memorial University)

As a body wastes away, leaving only bone behind, clues about when death occurred waste away with it.

Estimating the postmortem interval (PMI) of skeletonized remains is difficult without soft tissues to examine, and few quantitative methods exist to make a precise estimate only from bone. Forensic anthropologists may have to fall back on subjective, macroscopic observations and offer a wide timeframe spanning years or decades for when a victim may have died.

A team from Lincoln Memorial University, led by associate professor of anatomy Beatrix Dudzik, hopes to develop better methods by looking for biomarkers in bone marrow, which can survive for long periods of time after death along with the lipids it contains, and estimate PMI by looking at the degradation of those lipids. The research will involve placing the bodies of 20 donors at the outdoor Anthropological Research Facility at the University of Tennessee over a span of 2 years, as well as looking at samples from UT’s William Bass Donated Skeletal Collection, which contains bones with PMIs between about 1 to 30 years.

“This is building on a study that was done also at Lincoln Memorial University using skeletal muscle,” Dudzik told Forensic Magazine, crediting a 2013 study by researchers Paul L. Wood and Natalie R. Shirley as foundation for the new project. “They found some of the metabolomic byproducts of the decomposition process were predictive of a postmortem interval up to around a year.”

The research team will conduct the new research on bones, a collaboration between LMU’s DeBusk College of Osteopathic Medicine, LMU’s College of Veterinary Medicine, UT’s Forensic Anthropology Center and the Mayo Clinic, with help from a $377,535 U.S. Department of Justice grant awarded to Dudzik this week.

Wood, who was the lead author of the 2013 study and who runs the metabolomics lab at LMU’s College of Veterinary Medicine, will aid the research team in conducting mass spectrometry analysis on the lipids retrieved from the bones. The researchers will start by testing bone from specific parts of the body.

“Our experimental design samples three different areas: the calcaneus, so that’s going to be down on the foot, and then (the) proximal tibia, which will be around the knee area, as well as a vertebral body,” Dudzik explained. “This is very preliminary—we’re just trying to see if we have any differences, first of all, in the lipids in those different skeletal elements. And then, hopefully, with promising results, we can move on to sample other areas to see if there’s a range there that might be indicative of different parts of the body. Or we can say that all of these lipids are applicable to any elements of the skeleton.”

Teeth, which are often used in forensic anthropology to identify skeletal remains by matching dental records, could also be helpful in determining PMI, Dudzik added.

“We’ve done just a pilot study with teeth that have identified some really interesting lipids there,” she explained. “Oftentimes with archeological remains, if the bone had decomposed due to acidic soils, you’ll have the retention of teeth because they are protected by the enamel. So that’s another thing we’re hoping to look into.”

Funding for the project begins January 2018 and will last for two years, allowing donor bodies to decompose for that period of time before being tested, while in the meantime the team will also look at the dry skeletal remains available to them from the Bass collection.

“We’re hoping to get some good preliminary data within this 2-year span and then go from there, and hopefully get further funding to look at longer experimental postmortem intervals,” Dudzik said.

Researchers at Boston University School of Medicine have previously looked at environmental factors—specifically freeze-thaw cycles—to help determine a more accurate PMI. That study, published in 2016, studied the bones of white-tailed deer, frozen and thawed repeatedly in a controlled environment, and identified fine cracks in the bone that could be analyzed to determine how long they had been there.

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