MSCs: what’s in a name?

Whether they are "stem" or "stromal", from adult tissues or from umbilical cord blood, MSCs are being used for a lot of clinical trials. Read more

Mopping up immune troublemakers after transplant

Memory CD8+ T cells play an important role in kidney transplant rejection, and they resist drugs that would otherwise improve Read more

Tracking a frameshift through the ribosome

Ribosomal frameshifting, visualized through X-ray Read more

Heart

A spoonful of sugar helps infection detection

Congratulations to Kiyoko Takemiya, a postdoctoral fellow in Emory’s Division of Cardiology, working with W. Robert Taylor. At the recent American College of Cardiology meeting in Washington DC, she won first place in the competition for an ACC Foundation/ Herman K. Gold Young Investigators Award in Molecular and Cellular Cardiology.

The title of her research presentation was: A Novel Imaging Probe for the Detection of Subclinical Bacterial Infections Involving Cardiac Devices.

Takemiya, Taylor, and their colleagues (including Mark Goodman and Niren Murthy, formerly at Georgia Tech and now at UC Berkeley) developed a fluorescent probe that allows the detection of small levels of bacteria on cardiac devices. The probe was tested in rats, some of which had relatively mild local S. aureus infections. The fluorescent probe (PET is also under investigation) makes use of the properties of maltohexaose, a sugar that is taken up by bacteria but not mammalian cells.

Infection rates for implantable cardiac devices such as pacemakers have been rising, according to a 2012 paper in NEJM.

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Signs of future high blood pressure in college football players

College football players tend to have stiffer arteries than other college students, even before their college athletic careers have started, cardiology researchers have found.

Although football players had lower blood pressure in the pre-season than a control group of undergraduates, stiffer arteries could potentially predict players’ future high blood pressure, a risk factor for stroke and heart disease later in life.

Researchers studied 50 freshman American-style football players from two Division I programs, Georgia Tech and Harvard, in the pre-season and compared them with 50 healthy Emory undergraduates, who were selected to roughly match their counterparts in age and race. The research is part of a longer ongoing study of cardiovascular health in Georgia Tech college football players.

The results were presented Saturday at the American College of Cardiology meeting in Washington DC, by cardiology research fellow Jonathan Kim, MD. Kim worked with Arshed Quyyumi, MD, director of Emory’s Clinical Cardiovascular Research Institute, Aaron Baggish, MD, associate director of the Cardiovascular Performance Program at Massachusetts General Hospital, and their colleagues.

“It’s remarkable that these vascular differences are apparent in the pre-season, when the players are essentially coming out of high school,” says Kim. “We aim to gain additional insight by following their progress during the season.”

Despite being physically active and capable, more than half of college football players were previously found to develop hypertension by the end of their first season. Professional football players also tend to have higher blood pressure, even though other risk factors such as cholesterol and blood sugar look good, studies have found. Researchers have previously proposed that the intense stop-and-start nature of football as well as the physical demands of competitive participation, such as rapid weight gain, could play roles in making football distinctive in its effects on cardiovascular health.

In the current study, the control undergraduates had higher systolic and diastolic blood pressure than the football players: (football players: 111/63; control: 118/72). However, the football players displayed significantly higher pulse wave velocity, a measure of arterial stiffness (football: 6.5 vs control: 5.7). Pulse wave velocity is measured by noninvasive devices that track the speed of blood flow by calculating differences between arteries in the neck and the leg.

“It is known that in other populations, increased pulse wave velocity precedes the development of hypertension,” Kim says. “We plan to test this relationship for football players.”

The football players were markedly taller and larger than the control group (187 vs 178 centimeters in height, body mass index 29.2 vs 23.7). The football players also reported participating in more hours of weight-training per week than the control group (5.4 vs 2.6).

 

 

 

 

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Molecular signature of heart attack predicts longer-term outcomes

A molecular signature seen in blood from patients who are experiencing an acute heart attack may also predict the risk of cardiovascular death over the next few years, Emory researchers have found.

The results were presented Monday at the American College of Cardiology meeting in Washington DC by cardiovascular research fellow Nima Ghasemzadeh, MD. Ghasemzadeh is working with Arshed Quyyumi, MD, director of Emory’s Clinical Cardiovascular Research Center, as well as Greg Gibson, PhD, director of the Integrative Genomics Center at Georgia Tech.

Ghasemzadeh and colleagues examined 337 patients undergoing cardiac catheterization at Emory. Just 18 percent of the patients in this group were having a heart attack. This research is a reminder that the majority of patients who undergo cardiac catheterization, and thus are suspected of experiencing a heart attack, are not actually having one at that moment. Read more

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Cardiologists change their minds — not all at once

What happens when cardiologists learn that a widely performed procedure might not be as helpful as they once thought? Investigators at Emory have taken one of the first detailed looks at how geographical patterns in practice changed after publication of results from a large clinical trial.

The federal government has invested billions of dollars in comparative effectiveness research — comparing different healthcare interventions to determine which works best — with the aim of reducing variations in care. This paper shows that these types of investment can have the desired effect.

Recently Medscape Cardiology talked with lead author Arun Mohan, who is medical director for care coordination at Emory University Hospital, about his work. [You may have missed this news item over the holidays.] Read more

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BioArt: amyloid in the heart

What Abstract Expressionist artist painted this? Jackson Pollock?LewisW2013

Actually, the photo depicts amyloid plaques, a frequent topic in the context of Alzheimer’s disease. Pathologist William Lewis‘ photo reminds us that amyloid can also appear in the heart.

Amyloidosis of the heart is a set of complex diseases caused by the accumulation of cellular proteins that form an amyloid plaque. Although http://www.oakleyonorder.com/ amyloidosis was described more than 100 years ago, the causative proteins were not identified until recent chemical analyses were conducted. This image shows an amyloid plaque stained with Congo red stain and viewed through a polarized lens. The optical properties of the amyloid-forming protein cause it to appear green, while other matrix materials within the plaque appear as orange and blue.

The photo, which was one of the winners of the FASEB (Federation of American Societies for Experimental Biology) 2013 BioArt competition, was featured on NIH director Francis Collins’ blog this week.

Lewis, who studies the effects of antiretroviral drugs on the cardiovascular system in his laboratory, reports that he came across the amyloid tissue sample as part of his duties as director of cardiovascular pathology: “It was beautiful.”

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Fragile but potent: RNA delivered by nanoparticle

An intriguing image for November comes from biomedical engineer Mike Davis’ lab, courtesy of BME graduate student Inthirai Somasuntharam.

Each year, thousands of children undergo surgery for congenital heart defects. A child’s heart is more sensitive to injury caused by interrupting blood flow during surgery, and excess reactive oxygen species are a key source of this damage.

Macrophages with blue nuclei and red cytoskeletons, being treated with green nano particles. The particles carry RNA that shut off reactive oxygen species production.

Macrophages with blue nuclei and red cytoskeletons, being treated with green nano particles. The particles carry RNA that shut off reactive oxygen species production.

Davis and his colleagues are able to shut off cheap oakley reactive oxygen species at the source by targeting the NOX (NADPH oxidase*) enzymes that produce them. This photo, from a 2013 Biomaterials paper, shows green fluorescent nanoparticles carrying small interfering RNA. The RNA precisely shuts down one particular gene encoding a NOX enzyme. Eventually, similar nanoparticles may shield the heart from damage during pediatric heart surgery.

In the paper, Somasuntharam used particles made of a slowly dissolving polymer called polyketals. The particles delivered fragile but potent RNA molecules into macrophages, inflammatory cells that swarm into cardiac tissue after a heart attack. Davis and Georgia Tech colleague Niren Murthy previously harnessed this polymer to deliver drugs that can be toxic to the rest of the body.

The polyketal particles are especially well-suited for delivering a payload to macrophages, since those types of cells (as the name implies) are big eaters. Davis reports his lab has been working on customizing the particles so they can deliver RNA molecules into cardiac muscle cells as well.

*While we’re on the topic of NADPH oxidases, Susan Smith and David Lambeth have been looking for and finding potential drugs that inhibit them.

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Dealing with huff-puff? Think HFpEF

For this month’s Current Concept feature, we would like to explain a term from cardiology that is likely to become more prominent:

“Heart failure with preserved ejection fraction” (abbreviated as HFpEF and pronounced “heff-peff”).

Javed Butler, MD, an Emory expert on heart failure and deputy chief science officer for the American Heart Association, laid out in a recent seminar why this category of patients is so important. Look for more from him on this topic in the future.

Three points:

  1. The number of HFpEF patients is growing and they now make up the majority of patients with heart failure in the United States.
  2. No treatments have been proven to benefit them, in terms of reducing mortality.* In clinical studies, medications such as ACE inhibitors, angiotensin receptor blockers and beta-blockers have not helped.
  3. Once hospitalized, HFpEF patients have a high rate of readmission to the hospital within 30 days. The federal Medicare program is penalizing hospitals that have high rates of readmissions and heart failure is one of the largest contributors to readmissions.

The symptoms that drive people with HFpEF to the hospital are mainly fatigue and dyspnea, or shortness of breath, along with fluid in the lungs and swelling of the limbs. Along with heart failure, HFpEF patients often have conditions such as hypertension, anemia, diabetes, kidney disease or sleep apnea. Read more

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Packaging stem cells in capsules for heart therapy

Stem cell therapy for heart disease is happening. Around the world, thousands of heart disease patients have been treated in clinical studies with some form of bone marrow cells or stem cells. But in many of those studies, the actual impact on heart function was modest or inconsistent. One reason is that most of the cells either don’t stay in the heart or die soon after being introduced into the body.

Cardiology researchers at Emory have a solution for this problem. The researchers package stem cells in a capsule made of alginate, a gel-like substance. Once packaged, the cells stay put, releasing their healing factors over time.

Researchers used encapsulated mesenchymal stem cells to form a “patch” that was applied to the hearts of rats after a heart attack. Compared with animals treated with naked cells (or with nothing), rats treated with the capsule patches displayed increased heart function, reduced scar size and more growth of new blood vessels a month later. In addition, many more of the encapsulated cells stayed alive. Read more

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Molecular beacons shine path to cardiac muscle repair

Pure cardiac muscle cells, ready to transplant into a patient affected by heart disease.

That’s a goal for many cardiology researchers working with stem cells. Having a pure population of cardiac muscle cells is essential for avoiding tumor formation after transplantation, but has been technically challenging.

CardioMBs

Fluorescent beacons that distinguish cardiac muscle cells

Researchers at Emory and Georgia Tech have developed a method for Cheap Oakleys purifying cardiac muscle cells from stem cell cultures using molecular beacons.

Molecular beacons are tiny “instruments” that become fluorescent only when they find cells that have turned on certain genes. In this case, they target instructions to make a type of myosin, a protein found in cardiac muscle cells.

Doctors could use purified cardiac muscle cells to heal damaged areas of the heart in patients affected by heart attack and heart failure. In addition, the molecular beacons technique http://www.lependart.com could have broad applications across regenerative medicine, because it could be used with other types of cells produced from stem cell cultures, such as brain cells or insulin-producing islet cells.

The results are published in the journal Circulation.

“Often, we want to generate a particular cell population from stem cells for introduction into patients,” says co-senior author Young-sup Yoon, MD, PhD, professor of medicine (cardiology) and director of stem cell biology at Emory University School of Medicine. “But the desired cells often lack a readily accessible surface marker, or that marker is not specific enough, as is the case for cardiac muscle cells. This technique could allow us to purify almost any type of cell.”

Read more

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Possible diabetes drug/stent interaction

Diabetes and heart disease often intersect. Emory cardiologist Aloke Finn and his colleagues recently had two papers in the Journal of the American College of Cardiology and in Atherosclerosis describing a possible interaction between the widely used diabetes drug metformin and drug-eluting stents, which are used to to treat coronary artery disease. Anwer Habib, MD is the first author of both papers.

The stent props the once-blocked artery open while the drugs in the stents are supposed to prevent the artery from becoming blocked again. The drugs — usually mTOR inhibitors such as http://www.magliettedacalcioit.com everolimus or the newer zotarolimus — slow down cell growth, but this cuts both ways. The drugs slow down the recovery of the lining of the blood vessel and this may contribute to blood clot formation after stent placement.

In cultured human cells and in rabbits with implanted stents, Finn and colleagues showed that metformin augmented the effect of mTOR inhibitors on regrowth of the blood vessel lining. (However — the authors acknowledge that their animal model was not diabetic or atherosclerotic.)

The findings could mean that people taking metformin would need to take medications to prevent blood clotting medications for a longer time after stent placement. The authors say that clinical studies following patients who receive drug-eluting stents should look at metformin’s effects on blood clotting events. A study examining drug eluting stents in diabetic patients is in the works at Emory.

 

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