Weill Cornell science briefs May 2008

May 14, 2008

Stem Cells Might Contribute to Vascular Disease
Stem Cells Might Cause More Damage After Vascular Surgery

Physician-scientists believe that stem cells might play a harmful role in the body's reaction to trauma following common vascular surgery, like angioplasty. A team of scientists -- led by Dr. K. Craig Kent, Greenberg-Starr Professor and professor of surgery at Weill Cornell Medical College and chief of the Division of Vascular Surgery at NewYork-Presbyterian -- are currently studying how stem cells implant themselves in the wall of arteries and grow out of control. Commonly, a blockage re-forms following angioplasty (termed re-stenosis) near the area where the procedure was performed.

The researchers observed that a chemical in the body called transforming growth factor beta (TGF"), which stimulates tissue growth, is released in high levels inside the artery following the trauma of angioplasty. Dr. Kent believes this happens because TGF" beckons stem cells to the irritated area to heal the wound. This leads to the growth of dense, artery-blocking tissue. If the scientists can learn how to shut off this response, Dr. Kent believes great progress might be made in the treatment of recurring heart disease.

Cancer Stem Cells May Be at the Root of Brain Tumors

Stem Cells Resistant to Chemotherapy

Stem cells -- popularly known as a source of biological rejuvenation -- may play harmful roles in the body, specifically in the growth and spread of cancer. Amongst the wildly dividing cells of a tumor, scientists have located cancer stem cells. Physician-scientists from New York-Presbyterian/Weill Cornell are studying these cells with the hope of combating malignant cancers in the brain. Some patients' brain tumors respond to chemotherapy and some don't, according to Dr. John A. Boockvar, the Alvina and Willis Murphy Assistant Professor of Neurological Surgery and head of the Brain Tumor Research Group, at New York-Presbyterian/Weill Cornell, who believes that cancer stem cells may be the cause.

Dr. Boockvar is capturing and classifying these cancer stem cells in order to determine how they react to certain available drug therapies. Doing so will lead to more accurate and specific cancer diagnosis, allowing for tailored drug treatments. Results explaining the techniques used to harvest normal neural and brain-tumor-derived stem cells are described in a recent edition of the journal Neurosurgery.

New Device for Elderly With Heart Valve Failure

Less-Invasive Procedure for Those Previously Untreatable

In the hope of reaching a formerly untreatable patient group, clinician-researchers from NewYork-Presbyterian Hospital/Weill Cornell Medical Center are leading the minimally invasive Phase II EVEREST clinical trial with the aim of treating malfunctioning heart valves in the elderly. Many elderly people are too old, too weak, or too debilitated by their disease to be candidates for traditional surgery to fix the problem, according to Dr. Arash Salemi, attending cardiothoracic surgeon at NewYork-Presbyterian/Weill Cornell, and assistant professor of cardiothoracic surgery at Weill Cornell Medical College. Projections have estimated that by the year 2010, more than 50 million Americans will be over the age of 65. As many of these heart valve diseases occur in older age groups, more and more patients will be in need of therapy each year. And the proportion of high-risk/inoperable patients will also increase. The heart valves are trap doors that control blood flow between the chambers of the heart. With wear, they either become leaky or too tight. Symptoms of these conditions include shortness of breath and fatigue, and if left untreated, may often lead to death by heart failure or arrhythmia.

The new technique, already proven safe by a Phase I clinical trial in 2005, involves only a small incision through the skin in the groin. A small catheter is then guided up through the maze of the blood vessels of the circulatory system and into the targeted heart chamber. Then, a tiny metal clip is clamped into the area to stabilize the malfunctioning valve. This less-invasive method also means less morbidity and less recovery time -- as little as a one-day stay in the hospital compared to the usual five days.

Combating Stroke

Outfitting Device With Drugs to Prevent Future Stroke

Dr. Pierre Gobin is the inventor of the MERCI Retriever, a catheter corkscrew device that slips into the blood vessels of the brain to hook onto and then remove blood clots. But now, Dr. Gobin is working on another pioneering advancement: the combination of the MERCI device with a drug delivery system to protect the affected part of the brain as blockages are removed. Doing so might help to minimize damage to blood-starved brain tissue, while lowering the risks associated with removal of a blockage, such as reperfusion hemorrhage -- a form of bleeding caused by the weakening of blood vessels due to the absence of blood flow.

For the first time, Dr. Gobin and his team, in collaboration with faculty at Cornell University's School of Engineering in Ithaca, New York, have developed a novel microcatheter to successfully deliver neuroprotective drugs through the brain arteries of a rat. The compounds were infused both into an entire hemisphere of the brain, and into the basal ganglia, the deep brain structures that help start and control movement and which are often damaged by stroke.

Global Risk

Infection by Deadly Bacterium Can Be Prevented With Proper Sanitation

As urban sprawl spreads throughout the globe, so do poor urban ghettos and the infectious diseases that are perpetrated by unsanitary slum conditions. Weill Cornell researchers stationed in the urban slums of Salvador, Brazil, have discovered that certain unhealthy living conditions lead to transmission of leptospirosis, a life-threatening disease caused by the bacterium Leptospira. Over a half-million people are infected, killing 1 in 10, each year. The disease, which is characterized by fever, abdominal pain, and can lead to severe pulmonary bleeding, kidney damage and meningitis, is transmitted through animal contact (commonly rat urine).

Dr. Albert Ko, senior author of the study and physician-scientist from the Division of International Medicine and Infectious Disease at Weill Cornell Medical College, and his research team stationed at Oswaldo Cruz Foundation/Brazilian Ministry of Health in the city of Salvador, tested a group of 3,171 slum residents for Leptospira antibodies -- a marker of past infection with the bacterium.

The researchers identified several variables that raised the risk of infection within those who tested positive for past infection, including persons living at the bottom of valleys (raising flood risk), those around open sewers or near accumulated refuse, and those who saw rats or lived in the presence of chickens. The scientists also determined that socio-economic factors contributed to risk: an increase of only $1 (USD) per day in per capita household income was associated with a substantial 11 percent decrease in infection risk. The researchers believe that improving sanitation can greatly curb the rate of infection. The study is published in a recent issue of PLoS Neglected Tropical Diseases.
NewYork-Presbyterian Hospital/Weill Cornell Medical Center

NewYork-Presbyterian Hospital/Weill Cornell Medical Center, located in New York City, is one of the leading academic medical centers in the world, comprising the teaching hospital NewYork-Presbyterian and Weill Cornell Medical College, the medical school of Cornell University. NewYork-Presbyterian/Weill Cornell provides state-of-the-art inpatient, ambulatory and preventive care in all areas of medicine, and is committed to excellence in patient care, education, research and community service. Weill Cornell physician-scientists have been responsible for many medical advances -- from the development of the Pap test for cervical cancer to the synthesis of penicillin, the first successful embryo-biopsy pregnancy and birth in the U.S., the first clinical trial for gene therapy for Parkinson's disease, the first indication of bone marrow's critical role in tumor growth, and, most recently, the world's first successful use of deep brain stimulation to treat a minimally-conscious brain-injured patient. NewYork-Presbyterian, which is ranked sixth on the U.S.News & World Report list of top hospitals, also comprises NewYork-Presbyterian Hospital/Columbia University Medical Center, Morgan Stanley Children's Hospital of NewYork-Presbyterian, NewYork-Presbyterian Hospital/Westchester Division and NewYork-Presbyterian Hospital/The Allen Pavilion. Weill Cornell Medical College is the first U.S. medical college to offer a medical degree oversees and maintains a strong global presence in Austria, Brazil, Haiti, Tanzania, Turkey and Qatar. For more information, visit www.nyp.org and www.med.cornell.edu.

NewYork-Presbyterian/Weill Cornell Medical Center

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More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.

Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Healthy blood stem cells have as many DNA mutations as leukemic cells
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New method grows brain cells from stem cells quickly and efficiently
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NUS researchers confine mature cells to turn them into stem cells
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Researchers develop a new method for turning skin cells into pluripotent stem cells
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