Basic research presentations at 2016 American Heart Association Scientific Sessions: cell therapy for heart attack (mesenchymal stem cells) in animal models and role of CD73, gradual release drug for atrial fibrillation, how particles from stored blood affects blood vessels.
Mesenchymal Stem Cells Require CD73 Activity to Reduce Leukocyte Associated Inflammation Following Myocardial Ischemia-Reperfusion Injury
Nov.13, 1:30 pm, Science and Technology Hall- Basic Science Theater
Cell therapy, using the patient’s own cells to reduce damage to the heart after a heart attack, has been a hot topic. Mesenchymal stem cells are derived from the bone marrow and can’t replace heart muscle. But they do exert anti-inflammatory and anti-oxidative effects, Eric Shin, MD, Rebecca Levit, MD and colleagues show in a rat model of heart attack.
The researchers use the gel material alginate to encapsulate the cells, in a way previously described by Levit. They say this is the first study to demonstrate that mesenchymal stem cells reduce reactive oxygen species production in the heart. and that the molecule CD73, which degrades ATP/ADP into adenosine, is needed for the anti-inflammatory effect. CD73 is also a cancer immunotherapy target. Read more
More than 9 million people donate blood in the United States every year, according to the American Red Cross. Current guidelinesÂ say that blood can be stored for up to six weeks before use.
What happens to red blood cells while they are in storage, which transfusion experts call the â€œstorage lesionâ€? Multiple studies have shown that older blood may have sub-optimal benefits for patients receiving a transfusion. The reasons include: depletion of the messenger molecule nitric oxide, lysis of red blood cells and alterations in the remaining cellsâ€™ stiffness.
To that list, we could add the accumulation of microparticles, tiny membrane-clothed bags that contain proteins and RNA, which have effects on blood vessels and the immune system upon transfusion. Note: microparticles are similar to exosomes but larger â€“ the dividing line for size is about 100 nanometers. Both are much smaller than red blood cells.
EUH blood bank director John Roback recently gave a talk on the blood storage issue, and afterwards, cardiologist Charles Searles and research fellow Adam Mitchell were discussing their work on microparticles that come from red blood cells (RBCs). They have been examining the effects RBC-derived microparticles have on endothelial cells, which line blood vessels, and on immune cellsâ€™ stickiness.
Mitchell mentioned that he had some striking electron microscope images of microparticles and some of the particles looked like worms. With the aim of maintaining Lab Landâ€™s â€œCool Imageâ€ feature, I resolved to obtain a few of his photos, and Mitchell generously provided several.
â€œThose worms definitely had me mesmerized for a while,â€ he says.
In his talk, Roback described some of the metabolomics research he has been pursuing with Dean Jones. Instead of focusing only on how long blood should be stored, Robackâ€™s team is examining how much differences between donors may affect donated bloodâ€™s capacity to retain its freshness. Read more
Matthew Woodruff — Bali Pulendran lab
Kenneth Myers — James Zheng lab
Joshua Strauss — Elizabeth Wright lab
JoAnna Anderson — Francisco Alvarez lab
Alexey Tamas — Charles Searles lab
Emory’s Office of Postdoctoral Education is holding a Best Image contest. The deadline to vote is this Thursday, April 30. You can look at these beautiful images (and guess exactly what they are, based on what lab they come from), but to VOTE, you need to go to the OPE site.
This is part of the run up to their Postdoctoral Research Symposium at the end of May.
(Hat tip to Ashley Freeman in Dept of Medicine!)
Biomedical engineer Mike Davis reports he has obtained NHLBI funding to look into therapeutic applications of exosomes in cardiology. But wait. What are exosomes? Time for an explainer!
Exosomes are tiny membrane-wrapped bags, which form inside cells and are then spat out. Theyâ€™re about 100 or 150 nanometers in diameter. Thatâ€™s smaller than the smallest bacteria, and about as large as a single influenza or HIV virion. Theyâ€™re not visible under a light microscope, but are detectable with an electron microscope.
Scientific interestÂ in exosomes shot up after it was discovered that they can contain RNA, specifically microRNAs, which inhibit the activity of other genes. This could be another way in which cells talk to each other long-distance, besides secreting proteins or hormones. Exosomes are thus something like viruses, without the infectivity.
Since researchers are finding that microRNAs have potential as therapeutic agents, why not harness the vehicles that cells use to send microRNAs to each other? Similarly, if so much evidence points toward the main effect of cell therapy coming from what the cells make rather than the cells themselves, why not simply harvest what the cells make? Read more