Friday, November 27, 2009

Advanced Cell Technology seeks to test embryonic stem cells to treat blindness.

From the Los Angeles Times:
November 19, 2009 10:00 am

Stem cells could be used to remedy
formerly incurable eye defects which
cause blindness.

Patients with a rare eye disease could be the first to be treated with human embryonic stem cells.
Advanced Cell Technology Inc., a Santa Monica-based biotech company with labs in Massachusetts, announced today that it has asked the U.S. Food and Drug Administration for approval to test retinal cells grown from stem cells in 12 people with Stargardt’s macular dystrophy.
The disease is a childhood version of macular degeneration and affects about one in 10,000 kids. Patients typically begin to lose their central vision between the ages of 6 and 20. As SMD progresses, things may look blurry and distorted, and patients may have trouble adjusting to low light. About half of victims are legally blind by age 50. There is no cure.
Most cases occur when children inherent a faulty version of the ABCA4 gene or the CNGB3 gene from both parents. As a result, the photoreceptor cells in the retina don’t get enough fuel, and they atrophy.
ACT hopes to reverse this by supplying patients with new retinal pigment epithelium cells derived from human embryonic stem cells. The RPE cells have been shown to improve vision in animals, with one study restoring eye function in sick rats and mice to “near-normal” levels. Another study boosted rats’ vision to 70% that of healthy animals. No adverse side effects were found in any of the company’s pre-clinical studies, Dr. Robert Lanza, ACT’s chief scientific officer, said in an interview.
ACT proposes a Phase I/II trial designed to assess the safety and tolerability of its RPE cells. The company and its collaborators would like to recruit a dozen patients with advanced SMD at three sites: the Casey Eye Institute in Portland, Ore.; the University of Massachusetts Memorial Medical Center in Worcester; and the UMDNJ – New Jersey Medical School in Newark.
Amid much fanfare, Geron Corp. received FDA approval in January to use specialized nerve cells made out of human embryonic stem cells to treat a handful of patients paralyzed by spinal cord injuries. Those plans are on hold while the company conducts pre-clinical studies to address some safety concerns about its cells, known as GRNOPC1. Last month, Geron said it expected to initiate its clinical trial in the third quarter of 2010.
Since their creation in 1998, human embryonic stem cells have been a highly controversial area of medical research. The cells are derived from days-old human embryos, which gives them the ability to grow into any type of cell in the body. Some scientists – like those at ACT and Geron – envision using them to grow replacement tissues to treat sick patients. But many people are troubled by the fact that the stem cells are typically made by dismantling and destroying human embryos.
ACT has tried to sidestep the ethical debate by using a different method to create its stem cell lines. Instead of using an entire embryo, the company figured out a way to remove only a single blastomere cell from a three-day-old embryo and turn it into a cell line. Such single-cell biopsies are routinely performed in fertility clinics to screen embryos for devastating genetic diseases, and the procedure leaves the embryo intact. The RPE cells that would be used in the clinical trial were grown from one of the company’s single-blastomere cell lines, Lanza said.
The company is also making and testing RPE cells derived from induced pluripotent stem cells. So-called iPS cells behave like embryonic stem cells but are made by reprogramming mature cells taken from children or adults, not from embryos. However, the reprogramming process currently involves viruses and genetic manipulation techniques that make the cells unsuitable for human therapies.
Lanza said ACT decided to target Stargardt’s macular dystrophy first because it has been designated an “orphan disease” and could benefit from a faster regulatory review. The FDA has 30 days to respond to the company’s filing, made Wednesday, and the clinical trial could begin early next year.
If all goes well, the company plans to seek permission to use its RPE cells to treat age-related macular degeneration, Lanza said. That disorder is much more common, and it destroys the central vision of an estimated 1.75 million Americans.
-- Karen Kaplan
Photo: Scientists from Advanced Cell Technology remove a single cell from a days-old embryo, which was used to create a line of human embryonic stem cells. Stem cells made this way were grown into eye cells that the company hopes will treat patients with Stargardt's macular dystrophy. Credit: Associated Press photo/Advanced Cell Technology

Tuesday, November 17, 2009

Fructose May Raise Blood Pressure

Drinking more than two sweetened sodas a day boosts risk of hypertension, study finds

FRIDAY, Oct. 30 (HealthDay News) -- Here's a new reason to put down that sugary soft drink: Research suggests that a diet high in fructose, a common sweetener, boosts the risk of high blood pressure.
High-fructose corn syrup is found in many processed foods and beverages. Americans consume 30 percent more fructose now than 20 years ago, and researchers have linked higher fructose consumption to the growing obesity epidemic. But scientists weren't sure if a connection existed between fructose consumption and high blood pressure.
In a new study, Dr. Diana Jalal, of the University of Colorado Denver Health Sciences Center, and colleagues studied 4,528 adults without a history of high blood pressure. They examined their fructose intake and found that those who consumed more than 74 grams of fructose per day -- that's the equivalent of the amount in 2.5 sweetened soft drinks -- boosted their risk of high blood pressure by 28 percent to 87 percent, depending on the level of hypertension.
"These results indicate that high fructose intake in the form of added sugars is significantly and independently associated with higher blood pressure levels in the U.S. adult population with no previous history of hypertension," the study authors wrote, adding that future research is needed to determine if lowering fructose intake will also lower blood pressure.
The study findings were scheduled to be presented at the American Society of Nephrology's annual meeting, held Oct. 27 to Nov. 1 in San Diego.

More information
Learn about high blood pressure from the American Heart Association.
-- Randy Dotinga
SOURCE: American Society of Nephrology, news release, Oct. 29, 2009
Last Updated: Oct. 30, 2009
Copyright © 2009 ScoutNews, LLC. All rights reserved.

Tuesday, November 3, 2009

Significant arterial damage may occur after first cigarette, research suggests.

Smoking's Damage Swift, Irreversible
Just 1 Cigarette Can Stiffen Arteries in Young Smokers, Study Shows
By Bill Hendrick
WebMD Health News
Reviewed by Louise Chang, MD

Oct. 27, 2009 -- Cigarette smoking starts inflicting “very significant” damage on the arteries with the very first puffs taken by otherwise healthy young smokers, new research shows.
The damage worsens as time passes and is impossible to reverse, says researcher Stella Daskalopoulou, MD, of the McGill University Health Centre.
The study found that smoking just one cigarette increases the stiffness of the arteries in 18- to 30-year-old smokers by 25% after a treadmill exercise test. It was presented at the Canadian Cardiovascular Congress 2009 in Edmonton, Alberta.
As arteries stiffen, she says, the heart must work harder, increasing the risk for heart disease or stroke.
“Our results are significant because they suggest that smoking just a few cigarettes a day impacts the health of the arteries,” Daskalopoulou says in a news release. “This was revealed very clearly when these young people were placed under physical stress, such as exercise.”
She tells WebMD that the study compared the arterial stiffness of 10 young smokers, who puffed five to six cigarettes a day, to 10 nonsmokers. The median age of the participants was 21 years. Researchers, who included R.J. Doonan and other medical students under her supervision, measured arterial stiffness at rest and after exercise.
Arterial stiffness in all participants was measured using a method called applanation tonometry.
An initial arterial stiffness measurement was performed at rest for each subject to establish a baseline measure for all the participants. Smokers were instructed not to smoke for 12 hours prior to the test.
After the first meeting, the smokers completed two more tests on different days. For one test, they smoked a single cigarette and then repeated a treadmill exercise test. For the other test, smokers were asked to chew a piece of nicotine gum prior to the exercise test. Daskalopoulou found that after exercise:
• Arterial stiffness levels in nonsmokers dropped by 3.6%.
• Arterial stiffness in smokers increased by 2.2%.
• After one cigarette, it increased by 24.5% in the smokers.
• After nicotine gum, stiffness increased by 12.6% in the smokers.
What the study means, she tells WebMD, is that even light smoking in otherwise healthy people damages the arteries, compromising the ability to cope with physical stress, such as climbing stairs.
“The people tested were young and healthy,” she tells WebMD. “We found there was no significant difference at rest between smokers and nonsmokers, but then we got them to exercise, and the difference was clear.”
Cherry Wongtrakool, a pulmonary specialist at the Emory University School of Medicine in Atlanta, tells WebMD there’s no doubt that even one or two cigarettes impairs blood vessel function.
The question is, “how much of that change is going to be persistent,” which she says isn’t answered by the study.
“We know if you have any smoking in your personal history, that puts you at risk for a number of diseases, even if you are a former smoker,” Wongtrakool says.
Daskaloupoulou is working on another study now examining whether former smokers who recently stopped can recover some lung function, and if so, how long it takes.
“This study is very exciting,” Daskalopoulou tells WebMD. “The earlier you stop, my belief is, the faster some recovery will be, but I don’t believe the [arterial] system ever goes back to normal. If you stop early, the damage will be much smaller, but there will still be damage.”
She also says that young people who believe that a little smoking doesn’t hurt are wrong.
Beth Abramson, MD, spokeswoman for the Heart and Stroke Foundation of Canada and director of the Cardiac Prevention Center at St. Michael’s Hospital in Toronto, tells WebMD the study is stunning in that it shows clearly that “harmful effects of smoking show up immediately. This is more evidence to prove that smoking is horrendous to one’s health.”
Any smoking is bad, she says, because “it does the opposite of what nitroglycerin does, which is helps increase blood flow to the heart.”
She says even people who’ve smoked for decades can benefit from quitting, though “it’s going to take longer to take your risk down.”