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Entries in Cells (5)

Saturday
Jan262013

Genetically Modified Cells Could Prevent Death from HIV/AIDS, Study Finds

(NEW YORK) -- Using genetic modification to treat HIV could create cells that are resistant to the two major types of the virus, preventing it from evolving into AIDS, according to a new study.

Researchers at the Stanford University School of Medicine and the University of Texas at Austin used a method known as targeted trait stacking to paste a series of HIV-resistant genes into T cells — immune cells targeted by the AIDS virus — blocking infection at multiple stages and providing protection against R5-tropic and X4-tropic, the two separate forms of HIV. Any truly useful treatment for HIV would have to protect against both of these forms.

“We inactivated the CCR5 gene, and then introduced 3 additional genes,” Dr. Matthew Porteus, an associate professor of pediatrics at Stanford and lead investigator in the study, told ABC News. “When cells had all four of these traits, we found that after 25 days the cells were completely resistant to both types of HIV.”

One of the major obstacles to treating HIV is the high mutation rate of the virus. Patients must use a cocktail mix of drugs, known as Highly Active AntiRetroviral Therapy (HAART), in order to fight the virus at different stages.

“HIV is a great shape shifter,” said Sara Sawyer, an assistant professor of molecular genetics and microbiology at the University of Texas at Austin and co-author of the study.  “It can come up with new solutions, so a single drug does not work very well. That’s why HIV patients are given multiple drugs at once.”

Ideally, researchers hope to discover a cocktail of genes, not just drugs.  They informally call it genetic-HAART, and it would bolster a patient’s immune system with HIV-resistant T cells. While other non-resistant cells were being killed by the virus, these supplemented T cells would remain, strengthening the patient’s immune system and serving as an alternative to traditional HIV treatments.

“This method would give people a protected reservoir of T cells that would thwart off immune system collapse, and the secondary infections that give rise to AIDS,” said Sawyer.

The next steps in refining this particular approach to combating HIV/AIDS include finding the right cocktail of genes, and inserting them into T cells from AIDS patients. These modified T cells could then be used in animals to determine whether or not they remain resistant over time. These steps are required by the Food and Drug Administration before it can approve clinical trials, which could take 3-5 years.

“To develop novel therapies you have to be an optimist,” said Porteus. “The findings in this study are a proof of concept; we’ve proven this could work.”

The study was funded by the Foundation for AIDS Research and will be published in the Jan. 29 issue of the journal Molecular Therapy.

Copyright 2013 ABC News Radio

Thursday
Jun142012

Doctors Transplant Vein Grown from Patient's Own Cells

Comstock/Thinkstock(NEW YORK) -- Scientists in Sweden are reporting a medical first: a vein grown in a lab for a 10-year-old girl using her body's own cells.

Doctors are hailing the step as a milestone in tissue engineering, a field in which doctors grow windpipes, bladders, lungs and other organs to replace faulty ones while avoiding the dangerous, lifelong complications of organ transplants.

While a handful of doctors around the world have had success growing blood vessels and other organs and transplanting them into patients, doctors said this is the first time a vein has been lab-grown and successfully transplanted using cells and parts taken entirely from the human body.

"To many of us working in this field, it is a validation of what we believe will be a revolution in medicine," said Dr. Adam Katz, director of plastic surgery research at the University of Florida.

Suchitra Sumitran-Holgersson, one of the authors of a report on the transplant published Wednesday in the Lancet journal, said the experimental procedure could someday bring promise to patients needing new blood vessels for dialysis or coronary bypasses.

Sumitran-Holersson and her colleagues grew the vein for a 10-year-old girl who had a blockage in the vein connecting her intestines and spleen with her liver. The rare condition can cause life-threatening bleeding, delayed development and even death. The patients often need a graft of a vein to replace the blocked one.

In this new approach, doctors took about 3.5 inches of a vein from the groin of a 30-year-old deceased donor and, in the lab, scraped away all of the donor's cells, leaving just the protein scaffolding of the vein. Doctors then took cells from the bone marrow of the 10-year-old girl and seeded the vein scaffolding with them. Then, for two weeks, they waited for the cells to grow.

The result was a blood vessel engineered entirely from human tissue. When surgeons took the vein and used it to replace the faulty vein leading to the girl's liver, normal blood flow was restored almost immediately, the researchers said.

The vessel had to be repaired after nine months when hardened scar tissue in the girl's body put too much pressure on the transplanted vessel.

A year after the transplant, the girl has grown nearly 2.5 inches, gained 11 pounds and has even taken up light gymnastics. So far, her body also shows no signs that it will reject the vein. But doctors will have to make sure that the vein and the liver stay healthy.

"When we met her last week, she was somersaulting and talking away," Sumitran-Holgersson said. "So far, she is doing very well."

Even though the results are exciting, doctors remain cautious about their implications for patients who need vein grafts for more common conditions, such as dialysis or coronary bypasses. The process of harvesting a donor's vein and covering it with the girl's own cells was nearly as complicated and costly as the process for an organ transplant.

"The organization and resources required for this process are significant and would severely limit the applicability of the treatment strategy to large groups of patients," said Dr. William Marston, chief of vascular surgery at University of North Carolina Hospitals.

Some cardiovascular surgeons said many patients having coronary bypasses have no shortage of their own arteries and veins that can be used in those surgeries. And many patients can't wait for treatment while doctors grow a vein for them.

Also, the fact that the graft needed repair after a year is a concern.

"A uniform conduit such as a perfectly sized and available bioengineered vein would be of great utility, but it needs to last closer to a lifetime, not a year," said Dr. John Calhoon, a professor of head and thoracic surgery at the University of Texas Health Science Center.

Sumitran-Holgersson said more work will need to be done to work out the kinks in the process and to test it in other patients. But she remains optimistic about scientists' ability to create personalized blood vessels and other organs, reducing the need for a lifetime of drugs and surgeries.

"This is a very exciting technique and one that can greatly improve a patient's quality of life after transplantation," she said. "I think we're going to see quite a bit of this in the future."

Copyright 2012 ABC News Radio

Wednesday
Jun062012

Breast Cancer: Blood Test Spots Wayward Tumor Cells

Photodisc/Thinkstock(HOUSTON) -- A simple blood test can help predict the recurrence of breast cancer, a new study has found. The question is: Will it save lives?

The test detects cancer cells in the blood that have broken free from a tumor in the breast, like seeds that have fallen from a tree.

"The greater the number of seeds you sow, the greater the chance they'll take hold and grow," said study author Dr. Anthony Lucci, a surgical oncologist at the University of Texas MD Anderson Cancer Center in Houston.

Lucci and his team followed more than 300 women diagnosed with non-metastatic breast cancer for up to eight years, and found those who had cancer cells in their blood were five times more likely to relapse or die from breast cancer. Women with high levels of circulating tumor cells were 10 times more likely to relapse or die during the study period.

The results, published Tuesday in The Lancet Oncology, could help identify breast cancer patients with a high risk of recurrence. But the jury's still out on whether those patients should be monitored more frequently or treated more aggressively.

"I think we need to be patient," said Lucci, stressing the need for clinical trials to tease out the test's true value. "The natural urge is to run the test; have more information. But we don't know how best to use that information."

The test can reliably detect a single cancer cell in 7.5 milliliters of blood. But to become a tumor, that cell has to evade the body's immune system and find the perfect environment to grow and divide.

"In ongoing studies we're trying to characterize the cells that break free; figure out which ones are capable of setting up shop," Lucci said.

Nearly one-quarter of the women in the study had cancer cells in their blood, according to the study. But only 15 percent of them relapsed after undergoing treatment, meaning the vast majority did not.

Breast cancer treatment is currently guided by the size of the primary tumor, whether it has spread to lymph nodes or other organs, and molecular markers, like HER2, that open the door for targeted chemotherapies. But Lucci said cancer cells in the blood may be molecularly different from those in the primary tumor.

"We detected HER2-positive cells in the blood of patients with HER2-negative tumors," said Lucci, describing the results of a separate study he recently presented at the American Society of Clinical Oncology meeting in Chicago. "It raises the question of whether those patients could potentially benefit from other therapies."

But experts say it's too soon to tell whether having a single blood-borne cancer cell should influence treatment decisions.

"There's a substantial amount of interest in the technology of counting circulating tumor cells in the blood, but it's still a relatively new technology and questions remain as to how it can best guide clinical practice," said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. "At this point in time, it's difficult to say this technology would improve the care of women with breast cancer."

Until the test is proven to provide information that can refine and improve care for women with breast cancer, it's not ready for primetime, Lichtenfeld said. "This information is interesting, but ultimately it's how it impacts patient care that's most important."

Copyright 2012 ABC News Radio

Friday
Jul082011

Man Cancer-Free after Lab-Grown Windpipe Transplant

Adam Gault/Thinkstock(STOCKHOLM, Sweden) -- Doctors in Sweden have saved the life of a man who was diagnosed with cancer of the windpipe by replacing the bad organ with a good one made in a lab.

The procedure, performed less than a month ago at Karolinska University Hospital, proved to be so successful that the man is now considered cancer-free and is leaving the hospital on Friday.

Paolo Macchiarini, who carried out the windpipe transplant, admitted that before the operation the patient "was condemned to die."

If the man continues on the road to good health, it would mark a significant accomplishment in the field of regenerative medicine.  It's especially promising for those suffering from tracheal cancer or other diseases affecting the windpipe.

While the patient in Sweden was in critical condition, the decision was made to manufacture an artificial windpipe rather than wait for a suitable one from a cadaver.

The reason the transplant worked and why the new windpipe wasn't rejected was because scientists used cells from the patient to seed the organ.

They cautioned that this procedure may not be immediately effective with other complex organs such as the heart, which has thicker tissue.

Copyright 2011 ABC News Radio

Monday
Jan032011

Simple Blood Test to Detect Cancer?

Photo Courtesy - Getty Images(BOSTON) -- Researchers from Massachusetts General Hospital and health giant Johnson & Johnson are combining efforts to streamline a simple blood test that may be able to identify cancer cells in the blood stream of patients already diagnosed with a specific type of cancer.

But many experts question what place, if any, this test will have in the world of cancer prevention, early detection or even treatment.

The partnership is part of a nearly $30 million endeavor funded by Johnson & Johnson company Veridex and the advocacy group Stand Up to Cancer to develop and refine technology that will be able to accurately and quickly detect and analyze circulating tumor cells, the company said Monday.

Circulating tumor cells are a rare form of free-flowing cancer cells detached from the smallest of tumors and can be found at extremely low levels in the blood stream.

"For every one tumor cell in the blood there's over a billion normal blood cells in the circulation. So that's the big challenge for developing a test that can pull out one in a billion cells," said Dr. Daniel Haber, director of the cancer center at Massachusetts General Hospital in Boston.

CTC technology, approved by the Food and Drug Administration in 2004, is widely used in cancer centers to monitor a patient's response to treatment. But researchers now hope to expand its use to create a faster automated version that will analyze genetic components of a tumor and ultimately guide oncologists to personalize cancer treatments for patients.

"Harnessing the information contained in these cells in an in vitro clinical setting could enable tools to help select treatment and monitor how patients are responding," said Robert McCormack, head of technology innovation and strategy at Veridex.

Some cancer experts agreed the technology may be able to track some patients' cancer progression.

"It can help oncologists determine how well the drugs are working to kill cancer cells and it potentially could tell if the tumor returns at a later time," said Dr. Sarah Blair, associate professor of surgery in the division of surgical oncology at University of California San Diego.

Copyright 2011 ABC News Radio







ABC News Radio