Tug of war between Parkinson’s protein and growth factors

A “tug of war” situation exists between Parkinson's provocateur protein alpha-synuclein and the growth factor Read more

From stinging to soothing: fire ant venom may lead to skin treatments

Compounds derived from fire ant venom can reduce skin thickening and inflammation in a mouse model of psoriasis, Emory and Case Western scientists have Read more

Troublemaker cells predict immune rejection after kidney transplant

Evidence is accumulating that the presence of certain "troublemaker" memory T cells can predict the likelihood of belatacept-resistant immune Read more

hypoxia

Islet transplants from fish?

The shortage of human organ donors has led scientists to investigate animals as a potential source for transplantable organs or tissues. Pigs are often mentioned because of their size: similar to ours.

Recently, prospects for xenotransplantation brightened when Harvard geneticist George Church demonstrated the removal of dozens of endogenous retroviruses from the pig genome, in a tour de force of the CRISPR/Cas9 gene editing technique.

Emory researchers Susan Safley and Collin Weber have been exploring the possibility of using different animals for xenotransplantation: fish, specifically tilapia.

Why fish? This review details several advantages tilapia may offer in the field of islet transplant, but first – a reminder about islets.

Islets are the clusters of cells in the pancreas that produce insulin. Several clinical trials, including this one led by Emory’s Nicole Turgeon, have shown that islets isolated from deceased human donors can restore normal blood sugar regulation in patients with type 1 diabetes. Still, obstacles remain such as the shortage of human islets, and the loss of insulin independence over time, even with the use of drugs that hold off immune rejection.

For islet transplant, here are some of the proposed advantages presented by tilapia:

*tilapia have large, distinct islet organs called Brockmann bodies that are easy to isolate

*tilapia grow quickly and cost less to raise than pigs

*tilapia islets are resistant to hypoxia, thought to contribute to graft loss

*tilapia do not express alpha (1,3) gal, a carbohydrate structure present on mammalian cells that causes hyperacute rejection Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Clot dissolver tPA’s tardy twin could aid in stroke recovery

Emory researchers led by neurologist Manuel Yepes, MD have identified a protein released by neurons while the brain is recovering from a stroke. The results were published online today in Journal of Neuroscience.

The protein, called urokinase-type plasminogen activator or uPA, has been approved by the FDA to dissolve blood clots in the lungs. It has been tested in clinical trials in some countries as a treatment for acute stroke.

The Emory team’s findings suggest that in stroke, uPA’s benefits may extend beyond the time when doctors’ principal goal is dissolving the blood clot that is depriving the brain of blood.
Instead, uPA appears to help brain cells recover from the injuries induced by loss of blood flow. Treating mice with uPA after an experimental stroke can improve their recovery of motor function, the researchers found.

Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Hypoxia is bad, except when it’s good

Happy New Year!

Randy Trumbower and his colleagues in Emory’s Department of Rehabilitation Medicine recently published a study showing that “daily intermittent hypoxia,” combined with walking exercise, can help patients with incomplete spinal cord injury walk for longer times. What is it about being deprived of oxygen for short periods that has a positive effect?

This research was puzzling at first (at least to your correspondent) because “daily intermittent hypoxia” is a good description of the gasping and snorting interruptions of sleep apnea.

Sleep apnea is a very common condition that increases the risk of high blood pressure, diabetes, heart attack and stroke. On the other side of the coin, many endurance athletes have been harnessing the body’s ability to adapt to low oxygen levels – so-called altitude training — to increase their performance for years.

So we have an apparent clash: hypoxia is bad, except when it’s good. Looking closely, there are some critical differences between sleep apnea and therapeutic hypoxia. “The dose makes the poison,” right? Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Nitrite: from cured meat to protected heart

Nitrite may be best known as a food additive used in cured meats such as hot dogs, but medical researchers are studying how it could treat several conditions, including preventing damage to the heart after a heart attack.

Leaders in the nitrite field are meeting May 11 -13, 2011 at Emory Conference Center in Atlanta. One of the lead organizers is David Lefer, PhD, professor of surgery at Emory University School of Medicine and director of the Cardiothoracic Research Laboratory. Lefer discusses the beneficial effects of nitrite in the video below. More information about the meeting is available here.

Scientists think supplying a pulse of nitrite can reduce injury to heart tissue coming from the interruption of blood flow. Several clinical trials are now investigating nitrite as a therapy for conditions such as heart attack, ruptured aneurysm, sickle cell pain crisis and cardiac arrest.

Nitrite acts as the body’s reserve for nitric oxide, which turns on chemical pathways that relax blood vessels. Delivering nitric oxide directly into the body is expensive and hard to control. Unlike nitric oxide, whose lifetime in the body is a few seconds, nitrite is stable and stored in the body’s tissues and can be delivered in a variety of ways. It is converted into nitric oxide under conditions when the body needs it: lack of blood or oxygen. In addition, sodium nitrite has been used as part of a cyanide antidote kit. This means that safety data on large doses of nitrite in critically ill people is available.

In a 2005 paper published in the Journal of Clinical Investigation, Lefer and colleagues showed that nitrite can reduce damage to the hearts of mice after a simulated heart attack. More recently, assistant professor John Calvert and Lefer have shown that internally generated and stored nitrite is an important way that exercise protects the heart from a heart attack.

Some blood pressure studies underway in Europe have participants consume large amounts of beet juice as their source of nitrate, which is then converted to nitrite in the body.

A wave of public concern about nitrite and its relative nitrate in the 1970s focused on their presence in cured meats and their ability to form nitrosamines, which can be carcinogenic. Subsequent investigation showed that actually, most of the nitrite and nitrate in the average adult’s diet come from vegetables such as broccoli and spinach, and that antioxidants such as vitamin C can prevent nitrosamine formation.

Nathan Bryan, a speaker at the conference from UT-Houston, was featured in a recent television news story about herbal supplements designed to boost nitrite in the body.

Posted on by Quinn Eastman in Heart 2 Comments