Elevated troponin after exercise refines cardiac risk prediction

Elevated troponin levels in response to exercise can predict future outcomes in patients with coronary artery disease -- better than stress tests with Read more

For genetically altered mice/rats, freeze and recharge

Animals’ sperm (and occasionally embryos) can be carefully preserved in cold-resistant straws and stored in liquid Read more

Wallace H. Coulter Department of Biomedical Engineering

Transformative awards for Mocarski’s malleable cells, lung fibrosis

The National Institutes of Health has announced a five-year, $1.9 million Transformative Research Award to Emory virologist Edward Mocarski, PhD for his work on how the mechanisms of programmed cell death can be subverted.

Mocarski is Robert W. Woodruff professor of microbiology and immunology at Emory University School of Medicine and Emory Vaccine Center. His research, which originated in probing how cells commit suicide when taken over by viruses, could lead to advances in regenerative medicine and organ transplant.

Barker Mocarski

Thomas Barker, PhD (left) and Edward Mocarski, PhD (right)

The grant, funded through the National Institute of Allergy and Infectious Diseases, is one of nine “high-risk-, high-reward” Transformative Research Awards (13 recipients) announced by the NIH on October 6.

In the same group this year, Thomas Barker in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University received a Transformative Research Award for his research on mechanosensors + pulmonary fibrosis.

The Transformative Research Award program supports “exceptionally innovative, unconventional, paradigm-shifting research projects that are inherently risky and untested.” Emory has achieved only one other TRA since the program was established in 2009: Shuming Nie’s project on imaging to guide cancer surgery. Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Tools for illuminating brain function make their own light

Optogenetics has taken neuroscience by storm in recent years because the technique allows scientists to study the brain conveniently in animals, activating or inhibiting selected groups of neurons at the flip of a switch.  Most often, scientists use a fiber optic cable to deliver light into the brain.

Researchers at Emory and Georgia Tech have developed tools that could allow neuroscientists to put aside the fiber optic cable, and use a glowing protein from coral as the light source instead.

Biomedical engineering student Jack Tung and neurosurgeon/neuroscientist Robert Gross, MD, PhD have dubbed these tools “inhibitory luminopsins” because they inhibit neuronal activity both in response to light and to a chemical supplied from outside.

A demonstration of the luminopsins’ capabilities was published September 24 in the journal Scientific Reports.  The authors show that these tools enabled them to modulate neuronal firing, both in culture and in vivo, and modify the behavior of live animals.

Tung and Gross are now using inhibitory luminopsins to study ways to halt or prevent seizure activity in animals.

“We think that this approach may be particularly useful for modeling treatments for generalized seizures and seizures that involve multiple areas of the brain,” Tung says. “We’re also working on making luminopsins responsive to seizure activity: turning on the light only when it is needed, in a closed-loop feedback controlled fashion.” More here. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Deliver, but not to the liver

The potential of a gene-silencing technique called RNA interference has long enticed biotechnology researchers. It’s used routinely in the laboratory to shut down specific genes in cells. Still, the challenge of delivery has held back RNA-based drugs in treating human disease.

RNA is unstable and cumbersome, and just getting it into the body without having it break down is difficult. One that hurdle is met, there is another: the vast majority of the drug is taken up by the liver. Many current RNA-based approaches turn this apparent bug into a strength, because they seek to treat liver diseases. See these articles in The Scientist and in Technology Review for more.

But what if you need to deliver RNA somewhere besides the liver?

Biomedical engineer Hanjoong Jo’s lab at Emory/Georgia Tech, working with Katherine Ferrara’s group at UC Davis, has developed technology to broaden the liver-dominant properties of RNA-based drugs.

Hanjoong Jo, PhD

The results were recently published in ACS Nano. The researchers show they can selectively target an anti-microRNA agent to inflamed blood vessels in mice while avoiding other tissues.

“We have solved a major obstacle of using anti-miRNA as a therapeutic by being able to do a targeted delivery to only inflamed endothelial cells while all other tissues examined, including liver, lung, kidney, blood cells, spleen, etc showed no detectable side-effects,” Jo says. Read more

Posted on by Quinn Eastman in Heart Leave a comment

Regenerative Engineering & Medicine highlights

Last week on Friday, Lab Land attended the annual Regenerative Engineering & Medicine center get-together to hear about progress in this exciting area.

During his talk, Tony Kim of Georgia Tech mentioned a topic that Rose Eveleth recently explored in The Atlantic: why aren’t doctors using amazing “nanorobots” yet? Or as Kim put it, citing a recent review, “So many papers and so few drugs.”

[A summary: scaling up is difficult, testing pharmacokinetics, toxicity and efficacy is difficult, and so is satisfying the FDA.]

The talks Friday emerged from REM seed grants; many paired an Emory medical researcher with a Georgia Tech biomedical engineer. All of these projects take on challenges in delivering regenerative therapies: getting cells or engineered particles to the right place in the body.

For example, cardiologist W. Robert Taylor discussed the hurdles his team had encountered in scaling up his cells-in-capsules therapies for cardiovascular diseases to pigs, in collaboration with Luke Brewster. The pre-pig phase of this research is discussed in more detail here and here. Read more

Posted on by Quinn Eastman in Heart, Neuro Leave a comment

Stem cell/cardiology researcher Hee Cheol Cho joins Emory

Please welcome stem cell/cardiology researcher Hee Cheol Cho to Emory. Starting in September, Cho joined the Wallace H Counter Department of Biomedical Engineering at Georgia Tech and Emory, and Emory-Children’s Pediatric Research Center. He and his team will focus on developing gene-and cell-based therapies for cardiac arrhythmias. Their research will adding to and complement the research of several groups, such as those led by Chunhui Xu, Young-sup Yoon, Mike Davis and W. Robert Taylor.

Cho comes from Cedars-Sinai Medical Center in Los Angeles, where he specialized in understanding cardiac pacemaker cells, a small group of muscle cells in the sinoatrial node of the heart that initiate cardiac contraction. These cells have specialized electrophysiological properties, and much has been learned in the last few years about the genes that control their development.

Cho and colleagues from Cedars-Sinai recently published a paper in Stem Cell Reports describing how the gene SHOX2 can nudge embryonic stem cells into becoming cardiac pacemaker cells. Read more

Posted on by Quinn Eastman in Heart Leave a comment

Plaque erosion: heart attacks triggered by a whimper, not a bang

Cardiologist Bob Taylor and colleagues have a new paper in PLOS One this week, looking at the biomechanical forces behind plaque erosion.

Plaque erosion is a mechanism for blood clots formation in coronary arteries that is not as well-understood as its more explosive counterpart, plaque rupture. Plaque erosion disproportionally affects women more than men and is thought to account for most heart attacks in younger women (women younger than 50).

“We believe that this work has implications for our better understanding of the underlying biology of coronary artery disease in women,” Taylor says. The first author of the paper is biomedical engineering graduate student Ian Campbell, who now has his PhD. The team collaborated with cardiovascular pathologist Renu Virmani in Maryland.

Cardiologists have well-developed ideas for how plaque rupture works*; see the concept of vulnerable plaque. Cholesterol and inflammatory cells build up in the coronary arteries over several years. At one point in a particular artery, the plaque has a core of dying inflammatory cells, covered by a fibrous cap. If the cap is thin (the patterns of blood flows near the cap influence this), there is a risk that the cap will break and the contents of the core will spill out, triggering a blood clot nearby.

Plaque erosion is more mysterious and can occur more gradually, the researchers have found. Read more

Posted on by Quinn Eastman in Heart Leave a comment

Scaling up to a speck of dust

DNA bricks keep getting larger. In 2012, a team of researchers at Harvard described their ability to make self-assembling structures –made completely out of DNA — that were about the size of viruses (80 nanometers across).

Yonggang Ke, PhD

Now they’re scaling up, making bricks that are 1000 times larger and getting close to a size that could be barely visible to the naked eye.

The advances were reported in Nature Chemistry.

Who: a team of researchers at the Wyss Institute at Harvard led by Peng Yin, and including Yonggang Ke, PhD, now an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

At Emory, Ke and his team are continuing to design 3D DNA machines, with potential functions such as fluorescent nanoantennae, drug delivery vehicles and synthetic membrane channels.

How: The DNA brick method uses short, synthetic strands of DNA that work like interlocking Lego® bricks to build complex structures. Structures are first designed using a computer model of a molecular cube, which becomes a master canvas. Each brick is added or removed independently from the 3D master canvas to arrive at the desired shape. The DNA strands that would match up to achieve the desired structure are mixed together and self assemble — with the help of magnesium salts — to achieve the designed crystal structures.

“Therein lies the key distinguishing feature of our design strategy–its modularity,” Ke says. “The ability to simply add or remove pieces from the master canvas makes it easy to create virtually any design.”

What for: As part of this study the team demonstrated the ability to position gold nanoparticles less than two nanometers apart from each other along the crystal structure — a critical feature for future quantum computational devices and a significant technical advance for their scalable production.

More here.

Posted on by Quinn Eastman in Uncategorized Leave a comment

Need a really small number?

Biomedical engineer Yonggang Ke‘s “DNA origami” artwork appears on the cover of NKe-image-300x265ature Methods, as part of a celebration of the journal’s 10th anniversary. Ke designed self-assembling DNA strands that would form a cylinder and a ring structure, let them assemble, and obtained images with transmission electron microscopy. The height of the final image is 120 nanometers, smaller than the wavelengths of visible light and about the size of an influenza or HIV virion.

Posted on by Quinn Eastman in Uncategorized Leave a comment

What are exosomes?

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. They’re about 100 or 150 nanometers in diameter. That’s smaller than the smallest bacteria, and about as large as a single influenza or HIV virion. They’re not visible under a light microscope, but are detectable with an electron microscope.

Scientific interest 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

Posted on by Quinn Eastman in Heart Leave a comment

Pilot human trial for image-guided cancer surgery tool

The Spectropen, a hand-held device developed by Emory and Georgia Tech scientists, was designed to help surgeons see the margins of tumors during surgery.

Some of the first results from procedures undertaken with the aid of the Spectropen in human cancer patients were recently published by the journal PLOS One. A related paper discussing image-guided removal of pulmonary nodules was just published in Annals of Thoracic Surgery.

To test the Spectropen, biomedical engineer Shuming Nie and his colleagues have been collaborating with thoracic surgeon Sunil Singhal at the University of Pennsylvania.

As described in the PLOS One paper, five patients with cancer in their lungs or chest participated in a pilot study at Penn. They received an injection of the fluorescent dye indocyanine green (ICG) before surgery.

ICG is already FDA-approved for in vivo diagnostics and now used to assess cardiac and liver function. ICG accumulates in tumors more than normal tissue because tumors have leaky blood vessels and membranes. The Spectropen shines light close to the infrared range on the tumor, causing it to glow because of the fluorescent dye.

[This technique resembles the 5-aminolevulinic acid imaging technique for brain tumor surgery being tested by Costas Hadjipanayis, described in Emory Medicine.]

In one case from the PLOS One article, the imaging procedure had some tangible benefits, allowing the surgeons to detect the spread of cancerous cells when other modes of imaging did not. Read more

Posted on by Quinn Eastman in Cancer Leave a comment