RaMedz

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Volume 7, Issue 3

April 2016

The Medical Journal of the Ramaz Upper School

Blood-Borne DNA Pinpoints Tissue Damage By: David Grinberg ‘19 Cells die all the time, and they shed fragments of their DNA into the blood. Now, many research teams are cultivating new ways to trace the DNA to its original tissue, hoping to detect early stages of a disease or monitor its progression. Noninvasive analysis of cell death is an exciting area with limitless applications. A technique for tracing the origin of circulating DNA detected the expected type of cell death in people with pancreatic cancer, type 1 diabetes, multiple sclerosis, and brain injuries. Since 2011, doctors have been able to order a test for Down Syndrome that inspects the DNA shed by a fetus into a pregnant woman’s blood. This test determines whether the child will be born with Down Syndrome as well as many other diseases. Another potential solution in inspecting DNA is to look at the Methyl chemical groups. Scientists have discovered that each cell type has a certain DNA methylation pattern. In October 2015, a group led by Dennis Lo of The Chinese University of Hong Kong stated in the Proceedings of the National Academy of Sciences (PNAS) that they could identify those methylation patterns in circulating DNA.

Benjamin Glaser from the Hadassah Medical Center in Jerusalem has given a cheaper and simpler approach. They say that by scanning circulating DNA for those hotspots in people recently diagnosed with type 1 diabetes, they can find dying β cells. β cells are insulin-producing cells in the pancreas. Those tested revealed proof of dying β cells in the blood of people who had been given islet cell transplants. Islet cells are tiny clusters of cells scattered throughout the pancreas. Pancreatic islets contain several types of cells, including beta cells, that produce the hormone insulin. Insulin helps cells throughout the body absorb glucose from the bloodstream and use it for energy. These scans show potential signs of immune rejection of the islets in transplant patients. However, Methylation is not the only way to trace circulating DNA. In the magazine Cell, a team at the University of Washington in Seattle have created a test that relies on tissue-specific differences in how DNA is packaged in structures called nucleosomes. The team could then use those nucleosome fingerprints to trace circulating DNA to the cancerous tissue.

Many researchers plan to test the nucleosome and methylation approaches in larger groups of people. Many scientists think that this research will not get us anywhere. Although, scientists also once had the same position regarding Down Syndrome being picked up from fetal DNA in a pregnant woman’s blood.

Staff Editors-in-Chief Arianne Rothschild Yakira Markovich Gabriel Klapholz Jessica Fuzailof

Faculty Advisor Ms. Lenore Brachot


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