By HILARY HOWARD
Published: February 17, 2010
From the New York Times
ABOUT a year ago, a prescription eye-drop formula for glaucoma made beauty history by repackaging itself as an eyelash serum. Now long, thick lashes can be obtained with a prescription to Latisse (about $120 a month). Allergan, the maker of Latisse, has exclusive rights to bimatoprost, the Food and Drug Administration-approved ingredient behind lash growth, but that hasn’t stopped other makers of eyelash serums from claiming that their products also may strengthen eyelashes. This month, a new drugstore version, Concentrated Lash Boosting Serum by L’Oréal Paris, which includes centella asiatica, a plant extract, and arginine, an amino acid found in keratin, made its debut for $14.95.
Karen Grant, an analyst at NPD, a market research company, estimated that sales of lash enhancing products in department stores tripled in dollar volume last year when offerings by Lancôme ($39) and the niche brands Tarte ($65), Fusion Beauty ($89) and Cargo ($35) were introduced. Other companies include Jan Marini Skin Research, which offers a conditioner with a peptide complex ($160 a tube). RapidLash and Neulash, available for $49.95 and $150 a tube respectively, feature isopropyl cloprostenate, a prostaglandin analogue like bimatoprost.
However, "not every prostaglandin analogue is created equal," said Dr. Amy Wechsler, a New York dermatologist. Prostaglandin analogues are synthetic hormones that attach to natural prostaglandin receptors in the body. Dr. Wechsler compared the varying efficacy of all prostaglandin analogues in strengthening lashes to the claims that all vitamin A analogues (retinol, retinyl palmitate and retin-A) have equal effects in improving skin conditions, which they don’t, she said. (Dr. Wechsler is not involved in the promotion of any eyelash product, although she will promote Juvederm XC, Allergan’s dermal filler, next week.)
Robert Trow, chief executive of Rocasuba/RapidLash, stands behind his prostaglandin analogue, but he’s also enthusiastic about other ingredients in his product, like pumpkin-seed and licorice extracts and biotin. RapidLash is effective, he wrote in an e-mail message, due to “the synergistic combination of state-of-the-art peptides and vitamins."
Confused? Just remember you can still fake it — and get instant results — with a $5 tube of mascara.
Friday, March 26, 2010
Friday, March 19, 2010
Study sheds light on 'teenage night owl syndrome'
Students are going to sleep later and may be underperforming in class because they're not getting enough bright light in the morning, researchers say. Better school lighting may help.
By Thomas H. Maugh II from the L.A. Times
February 17, 2010
Riding in school buses in the early morning, then sitting in poorly lighted classrooms are the main reasons students have trouble getting to sleep at night, according to new research.
Teenagers, like everyone else, need bright lights in the morning, particularly in the blue wavelengths, to synchronize their inner, circadian rhythms with nature's cycles of day and night.
If they are deprived of blue light during the morning, they go to sleep an average of six minutes later each night, until their bodies are completely out of sync with the school day, researchers from Rensselaer Polytechnic Institute reported Tuesday in the journal Neuroendocrinology Letters.
The finding was made by fitting a group of students with goggles that blocked blue light and discovering that their circadian rhythms were significantly affected.
"These morning-light-deprived teenagers are going to bed later, getting less sleep and possibly underperforming on standardized tests," said lead author Mariana G. Figueiro, a sleep researcher at the institute's Lighting Research Center. "We are starting to call this the 'teenage night owl syndrome.' "
"This is a nice little preliminary study" that definitely needs to be replicated, said sleep researcher Mary A. Carskadon of Brown University, who was not involved in the research. "I think the big take-home message probably is that better lighting in the schools is a good idea."
Parents and teachers have been complaining loudly in recent years that teens stay up too late at night, then fall asleep in class the next morning and do poorly in school. The new findings provide a possible explanation for the problem.
At the root of the research is the circadian rhythm, the body's natural sleep and waking cycle. Even though the Earth makes a full rotation in 24 hours, the body's circadian cycle is about 24 hours and six minutes long. The cycle is mediated by a chemical called melatonin. The body starts to produce it about two hours before it is time to fall asleep and, in the absence of light, melatonin is released about six minutes later each day.
That is why people in dark rooms, caves or other locations with no external time cues will fall asleep about six minutes later each day, so that their sleep-wake cycles slowly drift in and out of alignment with the outside world.
In the study, Figueiro and Mark Rea, director of the Lighting Research Center, studied 11 students at Smith Middle School in Chapel Hill, N.C., which was designed so that a lot of sunlight reaches classrooms.
On a Friday night, the researchers measured what time the 11 students' bodies began releasing melatonin. On Monday morning, the students were sent to school with orange goggles that blocked most blue light from their eyes to mimic the conditions found in many -- if not most -- schools.
By the end of the week, the students were releasing melatonin 30 minutes later in the evening -- an average of six minutes per day -- and going to sleep correspondingly later.
"This is our first field study," Figueiro said. "We would like to replicate it in larger studies. Also for longer periods of time. We would also like to determine if you can see an impact on performance."
If the findings are replicated, a variety of solutions are available. Ideally, new schools would be built to allow more natural sunlight into the classrooms. Students could also be exposed to more sunlight outside.
Incandescent lights should never be used in classrooms because "they are heavy on yellow and red, and the circadian system is not tuned to those colors," Figueiro said. "You want incandescent light sources in the evening."
Some fluorescent lights are also not very good. Most that are currently used produce orange or reddish light, but it is now possible to buy bulbs that emit more blue.
thomas.maugh@
latimes.com
Copyright © 2010, The Los Angeles Times
By Thomas H. Maugh II from the L.A. Times
February 17, 2010
Riding in school buses in the early morning, then sitting in poorly lighted classrooms are the main reasons students have trouble getting to sleep at night, according to new research.
Teenagers, like everyone else, need bright lights in the morning, particularly in the blue wavelengths, to synchronize their inner, circadian rhythms with nature's cycles of day and night.
If they are deprived of blue light during the morning, they go to sleep an average of six minutes later each night, until their bodies are completely out of sync with the school day, researchers from Rensselaer Polytechnic Institute reported Tuesday in the journal Neuroendocrinology Letters.
The finding was made by fitting a group of students with goggles that blocked blue light and discovering that their circadian rhythms were significantly affected.
"These morning-light-deprived teenagers are going to bed later, getting less sleep and possibly underperforming on standardized tests," said lead author Mariana G. Figueiro, a sleep researcher at the institute's Lighting Research Center. "We are starting to call this the 'teenage night owl syndrome.' "
"This is a nice little preliminary study" that definitely needs to be replicated, said sleep researcher Mary A. Carskadon of Brown University, who was not involved in the research. "I think the big take-home message probably is that better lighting in the schools is a good idea."
Parents and teachers have been complaining loudly in recent years that teens stay up too late at night, then fall asleep in class the next morning and do poorly in school. The new findings provide a possible explanation for the problem.
At the root of the research is the circadian rhythm, the body's natural sleep and waking cycle. Even though the Earth makes a full rotation in 24 hours, the body's circadian cycle is about 24 hours and six minutes long. The cycle is mediated by a chemical called melatonin. The body starts to produce it about two hours before it is time to fall asleep and, in the absence of light, melatonin is released about six minutes later each day.
That is why people in dark rooms, caves or other locations with no external time cues will fall asleep about six minutes later each day, so that their sleep-wake cycles slowly drift in and out of alignment with the outside world.
In the study, Figueiro and Mark Rea, director of the Lighting Research Center, studied 11 students at Smith Middle School in Chapel Hill, N.C., which was designed so that a lot of sunlight reaches classrooms.
On a Friday night, the researchers measured what time the 11 students' bodies began releasing melatonin. On Monday morning, the students were sent to school with orange goggles that blocked most blue light from their eyes to mimic the conditions found in many -- if not most -- schools.
By the end of the week, the students were releasing melatonin 30 minutes later in the evening -- an average of six minutes per day -- and going to sleep correspondingly later.
"This is our first field study," Figueiro said. "We would like to replicate it in larger studies. Also for longer periods of time. We would also like to determine if you can see an impact on performance."
If the findings are replicated, a variety of solutions are available. Ideally, new schools would be built to allow more natural sunlight into the classrooms. Students could also be exposed to more sunlight outside.
Incandescent lights should never be used in classrooms because "they are heavy on yellow and red, and the circadian system is not tuned to those colors," Figueiro said. "You want incandescent light sources in the evening."
Some fluorescent lights are also not very good. Most that are currently used produce orange or reddish light, but it is now possible to buy bulbs that emit more blue.
thomas.maugh@
latimes.com
Copyright © 2010, The Los Angeles Times
Friday, March 5, 2010
Dark Chocolate May Lower Stroke Risk
But these sweet findings aren't conclusive, researchers say
By Randy Dotinga
HealthDay Reporter
THURSDAY, Feb. 11 (HealthDay News) -- Just in time for Valentine's Day comes word that eating dark chocolate appears to lower your risk of stroke or lessen the likelihood of death after a stroke.
But the findings, based on a review of existing research, aren't conclusive, and they don't prove that chocolate is good for your heart. And dietitians say too much chocolate can be harmful.
Still, two of the three studies analyzed in the review provide yet another suggestion that health benefits lurk in chocolate, dark chocolate in particular, said review co-author Dr. Gustavo Saposnik.
If choosing among white chocolate, milk chocolate or dark chocolate, "I'd definitely go with the dark chocolate," said Saposnik, director of the Stroke Research Unit at St. Michael's Hospital in Toronto.
The review authors, who found three studies on chocolate consumption and stroke between 2001 and 2009, are scheduled to report their findings at the American Academy of Neurology's annual meeting in Toronto in April.
One study found no significant association between chocolate consumption and risk of stroke or death from stroke. But another found that the stroke rate was 22 percent lower in people who ate chocolate once a week, and a third reported that death from stroke was 46 percent lower in those who ate 50 grams of chocolate once a week.
The health benefit may come from antioxidants called flavonoids that are present in chocolate, Saposnik said. Antioxidants are thought to prevent cell damage.
In years past, "the message was that chocolate consumption might be associated with higher LDL [bad] cholesterol or perhaps higher incidence of cardiovascular disease," he said. "Today, we know that all chocolates are not the same."
So, should you and your sweetheart add dark chocolate to your diet? "I'm not sure we can provide any recommendation at this time," Saposnik said.
For one thing, it's possible that some factor other than chocolate could be helping lower the risk of stroke. Those who eat more chocolate could be wealthier and have better access to health care, for instance, or go to the gym more often.
Saposnik said more studies will help clarify the association between chocolate and stroke risk.
For now, said registered dietitian Katie Clark, "caution should be taken not to promote chocolate as a health food," even though it's fine in moderation.
Chocolate is a major source of saturated fat, which raises bad cholesterol and boosts heart disease risk, said Clark, an assistant clinical professor at the University of California at San Francisco.
But Keith-Thomas Ayoob, an associate professor at Albert Einstein College of Medicine in New York City who studies nutrition, said chocolate does have its benefits. "Several studies indicate that even a little chocolate can help reduce blood pressure and increase blood flow through the arteries. Both are good for heart health," he said. "It's nice to know that chocolate isn't bad for you, assuming you eat modest amounts and don't become overweight by overeating it."
By Randy Dotinga
HealthDay Reporter
THURSDAY, Feb. 11 (HealthDay News) -- Just in time for Valentine's Day comes word that eating dark chocolate appears to lower your risk of stroke or lessen the likelihood of death after a stroke.
But the findings, based on a review of existing research, aren't conclusive, and they don't prove that chocolate is good for your heart. And dietitians say too much chocolate can be harmful.
Still, two of the three studies analyzed in the review provide yet another suggestion that health benefits lurk in chocolate, dark chocolate in particular, said review co-author Dr. Gustavo Saposnik.
If choosing among white chocolate, milk chocolate or dark chocolate, "I'd definitely go with the dark chocolate," said Saposnik, director of the Stroke Research Unit at St. Michael's Hospital in Toronto.
The review authors, who found three studies on chocolate consumption and stroke between 2001 and 2009, are scheduled to report their findings at the American Academy of Neurology's annual meeting in Toronto in April.
One study found no significant association between chocolate consumption and risk of stroke or death from stroke. But another found that the stroke rate was 22 percent lower in people who ate chocolate once a week, and a third reported that death from stroke was 46 percent lower in those who ate 50 grams of chocolate once a week.
The health benefit may come from antioxidants called flavonoids that are present in chocolate, Saposnik said. Antioxidants are thought to prevent cell damage.
In years past, "the message was that chocolate consumption might be associated with higher LDL [bad] cholesterol or perhaps higher incidence of cardiovascular disease," he said. "Today, we know that all chocolates are not the same."
So, should you and your sweetheart add dark chocolate to your diet? "I'm not sure we can provide any recommendation at this time," Saposnik said.
For one thing, it's possible that some factor other than chocolate could be helping lower the risk of stroke. Those who eat more chocolate could be wealthier and have better access to health care, for instance, or go to the gym more often.
Saposnik said more studies will help clarify the association between chocolate and stroke risk.
For now, said registered dietitian Katie Clark, "caution should be taken not to promote chocolate as a health food," even though it's fine in moderation.
Chocolate is a major source of saturated fat, which raises bad cholesterol and boosts heart disease risk, said Clark, an assistant clinical professor at the University of California at San Francisco.
But Keith-Thomas Ayoob, an associate professor at Albert Einstein College of Medicine in New York City who studies nutrition, said chocolate does have its benefits. "Several studies indicate that even a little chocolate can help reduce blood pressure and increase blood flow through the arteries. Both are good for heart health," he said. "It's nice to know that chocolate isn't bad for you, assuming you eat modest amounts and don't become overweight by overeating it."
Friday, February 26, 2010
Saffron may help reverse Macular Degeneration
From the UK's Daily Mail:
By Fiona Macrae
Last updated at 12:01 AM on 06th February 2010
It is one food colouring that you won't mind giving to the family.
Research has shown that saffron, which gives chicken korma and paella their yellow colour, helps keep vision sharp.
Test findings suggest the spice reverses age-related macular degeneration, or AMD, the most common cause of blindness in old people.
'Patients' vision improved after taking the saffron pill,' said Professor Silvia Bisti, of the University of Sydney, who carried out the research.
'When they were tested with traditional eye charts, a number of them could read one or two lines smaller than before, while others reported they could read newspapers and books again.'
The finding is timely as it is thought the number of AMD sufferers will treble in the next 25 years as the population ages.
It currently affects a quarter of over-60s in the UK and more than half of over-75s.
There are few treatments for the condition - and no cure.
While peripheral vision is not affected, the damage to central vision leads to many sufferers being registered as blind or partially sighted.
Saffron has actually been used in traditional medicine for centuries to treat a range of ailments, though Professor Bisti is the first to look at its effects on eyesight.
In tests carried out in Italy - where saffron is widely cultivated - pensioners with AMD were given a daily saffron pill for three months followed by a dummy drug for a further three months.
A second group took the supplements in the reverse order. Twenty-five took part in all.
'All patients experienced improvements in their vision while taking the saffron pill,' Professor Bisti said. 'But when they stopped taking it, the effect quickly disappeared.'
She added: 'The chemistry of saffron is quite complex. It is well-known as an anti- oxidant but no one has explored its effects on eyesight before.'
She believes saffron, which is widely used in Spanish and Indian cooking, affects the amount of fat stored by the eye, making vision cells 'tougher and more resilient'.
Saffron is used in traditional medicine for treating conditions including cancerous tumours and depression. The spice also has properties which encourage oxygen flow and prevents cell death.
Researchers are now hoping to discover the ideal dosage. They will also look at saffron's ability to treat genetic eye diseases that can cause life-long blindness.
By Fiona Macrae
Last updated at 12:01 AM on 06th February 2010
It is one food colouring that you won't mind giving to the family.
Research has shown that saffron, which gives chicken korma and paella their yellow colour, helps keep vision sharp.
Test findings suggest the spice reverses age-related macular degeneration, or AMD, the most common cause of blindness in old people.
'Patients' vision improved after taking the saffron pill,' said Professor Silvia Bisti, of the University of Sydney, who carried out the research.
'When they were tested with traditional eye charts, a number of them could read one or two lines smaller than before, while others reported they could read newspapers and books again.'
The finding is timely as it is thought the number of AMD sufferers will treble in the next 25 years as the population ages.
It currently affects a quarter of over-60s in the UK and more than half of over-75s.
There are few treatments for the condition - and no cure.
While peripheral vision is not affected, the damage to central vision leads to many sufferers being registered as blind or partially sighted.
Saffron has actually been used in traditional medicine for centuries to treat a range of ailments, though Professor Bisti is the first to look at its effects on eyesight.
In tests carried out in Italy - where saffron is widely cultivated - pensioners with AMD were given a daily saffron pill for three months followed by a dummy drug for a further three months.
A second group took the supplements in the reverse order. Twenty-five took part in all.
'All patients experienced improvements in their vision while taking the saffron pill,' Professor Bisti said. 'But when they stopped taking it, the effect quickly disappeared.'
She added: 'The chemistry of saffron is quite complex. It is well-known as an anti- oxidant but no one has explored its effects on eyesight before.'
She believes saffron, which is widely used in Spanish and Indian cooking, affects the amount of fat stored by the eye, making vision cells 'tougher and more resilient'.
Saffron is used in traditional medicine for treating conditions including cancerous tumours and depression. The spice also has properties which encourage oxygen flow and prevents cell death.
Researchers are now hoping to discover the ideal dosage. They will also look at saffron's ability to treat genetic eye diseases that can cause life-long blindness.
Saturday, February 20, 2010
Dr. Mandelman on CBC Maritime Noon Show
Hi all!
Dr. Mandelman was recently on the Maritime Noon Show with Costas Halavrezos answering questions on eyes and vision.
Visit:
http://www.cbc.ca/maritimenoon/2010/02/recruiting-memories-from-a-new-generation-of-veterans-response-to-show-on-snow-days-phone-in-dr-toby.html
to hear the show.
You just need to click on the play button near the bottom of the screen. Dr. Mandelman's portion begins about 15 min into the session. You can slide the player manually to begin playback at any time.
Enjoy!
Dr. Mandelman was recently on the Maritime Noon Show with Costas Halavrezos answering questions on eyes and vision.
Visit:
http://www.cbc.ca/maritimenoon/2010/02/recruiting-memories-from-a-new-generation-of-veterans-response-to-show-on-snow-days-phone-in-dr-toby.html
to hear the show.
You just need to click on the play button near the bottom of the screen. Dr. Mandelman's portion begins about 15 min into the session. You can slide the player manually to begin playback at any time.
Enjoy!
Friday, February 12, 2010
Eye test could diagnose Alzheimer's Disease
From the UK Telegraph:
A simple eye test carried out by your optician could pick up Alzheimer's Disease years before it develops and lead to early treatment to stop it in its tracks, claim scientists.
By Richard Alleyne, Science Correspondent
Published: 2:29PM GMT 14 Jan 2010
They say the quick, noninvasive and cheap test, which only involves applying eye-drops and then taking a photo with an infra-red camera, could revolutionise detection of dementia. Once diagnosed, treatment could begin immediately.
"Few people realise that the retina is a direct, albeit thin, extension of the brain," said Professor Francesca Cordeiro, lead author at University College London.
"It is entirely possible that in the future a visit to an eye doctor to check on your eyesight will also be a check on the state of your brain."
The technique, which is just starting human trials and could be available within two years, involves highlighting nerve cell damage in the eye using a chemical marker that glows when it finds it.
This can either be administered as an injection in the arm or eye-drops.
Once the substance is in the body it seeks out nerve cells that are dying and chemically marks them. All opticians and doctors need then do is use an infrared camera to take a picture of the eye and count how many dots appear in the photo.
Researchers, who published their findings in the journal Cell Death & Disease, have calculated that anything more than 20 could indicate the early onset of Alzheimer's.
Professor Cordeiro, who worked with Professor Stephen Moss, said: "The death of nerve cells is the key event in all neuro-degenerative disorders – but until now it has not been possible to study cell death in a living eye.
"Early diagnosis of Alzheimer's is critical in order to stop and reverse the cell death before it is too late. Once brains cells are dead there is no way to revive them.
"If you catch Alzheimer's Disease early enough you can slow it down and even reinvigorate the cells."
Alzheimer's charities welcomed the research and said it could change the way the disease is studied, diagnosed and monitored.
Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: ""We know as Alzheimer's disease develops, cells in the brain die and the brain shrinks.
"The study of this disease has been hampered by the difficulty of following the progress directly in the human brain. This research is very exciting as it opens up the possibility of observing individual cells on the human retina using a relatively non-invasive procedure.
"In the longer term this technique could be used for diagnostic purposes or to help researchers monitor the effects of drugs under development. However, much more research needs to be done before we know if we can get to this stage."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "Although this study uses animals, it is hoped that the technique can be modified for human use. These findings have the potential to transform the way we diagnose Alzheimer's, greatly enhancing efforts to develop new treatments and cures.
"If we spot Alzheimer's in its earliest stages, we may be able to treat and reverse the progression of the disease as new treatments are developed. Dementia scientists currently lack a way of assessing the brain's responses to new treatments in real-time. This technique may help overcome that obstacle."
Alzheimer's is the most common form of dementia, which affects around 700,000 people in the UK.
One million Britons are expected to develop dementia in the next 10 years.
A simple eye test carried out by your optician could pick up Alzheimer's Disease years before it develops and lead to early treatment to stop it in its tracks, claim scientists.
By Richard Alleyne, Science Correspondent
Published: 2:29PM GMT 14 Jan 2010
British researchers have developed a technique that highlights nerve cell damage in the retina of the eye which they have proved correlates exactly to nerve cell damage in the brain.
They say the quick, noninvasive and cheap test, which only involves applying eye-drops and then taking a photo with an infra-red camera, could revolutionise detection of dementia. Once diagnosed, treatment could begin immediately.
"Few people realise that the retina is a direct, albeit thin, extension of the brain," said Professor Francesca Cordeiro, lead author at University College London.
"It is entirely possible that in the future a visit to an eye doctor to check on your eyesight will also be a check on the state of your brain."
The technique, which is just starting human trials and could be available within two years, involves highlighting nerve cell damage in the eye using a chemical marker that glows when it finds it.
This can either be administered as an injection in the arm or eye-drops.
Once the substance is in the body it seeks out nerve cells that are dying and chemically marks them. All opticians and doctors need then do is use an infrared camera to take a picture of the eye and count how many dots appear in the photo.
Researchers, who published their findings in the journal Cell Death & Disease, have calculated that anything more than 20 could indicate the early onset of Alzheimer's.
Professor Cordeiro, who worked with Professor Stephen Moss, said: "The death of nerve cells is the key event in all neuro-degenerative disorders – but until now it has not been possible to study cell death in a living eye.
"Early diagnosis of Alzheimer's is critical in order to stop and reverse the cell death before it is too late. Once brains cells are dead there is no way to revive them.
"If you catch Alzheimer's Disease early enough you can slow it down and even reinvigorate the cells."
Alzheimer's charities welcomed the research and said it could change the way the disease is studied, diagnosed and monitored.
Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: ""We know as Alzheimer's disease develops, cells in the brain die and the brain shrinks.
"The study of this disease has been hampered by the difficulty of following the progress directly in the human brain. This research is very exciting as it opens up the possibility of observing individual cells on the human retina using a relatively non-invasive procedure.
"In the longer term this technique could be used for diagnostic purposes or to help researchers monitor the effects of drugs under development. However, much more research needs to be done before we know if we can get to this stage."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "Although this study uses animals, it is hoped that the technique can be modified for human use. These findings have the potential to transform the way we diagnose Alzheimer's, greatly enhancing efforts to develop new treatments and cures.
"If we spot Alzheimer's in its earliest stages, we may be able to treat and reverse the progression of the disease as new treatments are developed. Dementia scientists currently lack a way of assessing the brain's responses to new treatments in real-time. This technique may help overcome that obstacle."
Alzheimer's is the most common form of dementia, which affects around 700,000 people in the UK.
One million Britons are expected to develop dementia in the next 10 years.
Sunday, February 7, 2010
Crafting Light-Sensing Cells from Human Skin
From Technology Review:
Photoreceptors created from induced pluripotent stem cells.
By Janelle Weaver
Think twice the next time you wipe a few flecks of dandruff from your shoulder. You might be shedding cells that may someday restore human vision.
Thomas Reh and colleagues at the University of Washington, in Seattle, have generated light-sensing retinal cells, called photoreceptors, from adult human skin cells. They then transplanted the cells into a mouse retina, showing that the photoreceptors integrated normally into the surrounding tissue. This technological feat raises hopes for the development of treatments for retinal diseases, such as retinitis pigmentosa and macular degeneration, which cause visual impairment or blindness in millions of people in the U.S.
Researchers used induced pluripotent stem (iPS) cell technology, activating a handful of genes in skin cells in order to revert them to a flexible embryonic state. They then used previously developed methods to differentiate the cells into photoreceptors. While Reh's team has done similar experiments using embryonic stem cells, iPS cells are a preferable source for cell replacement therapies because they can be derived from the patient. Skin cells are a ready source of cells that are tissue-matched to the recipient, bypassing problems associated with immune rejection of stem-cell transplants.
The cells also provide a new way to study retinal degeneration diseases and to identify drug targets. Retinitis pigmentosa, for example, is an inherited disorder in which the photoreceptors begin to die. Retinal cells derived from a patient with the disease harbor all the genetic mutations that contributed to the patient's disease, so scientists can try to determine the molecular mechanisms that lead to cell death. They can then use the cells to screen for molecules that can slow or stop the damage.
"There are no good drugs to slow photoreceptor degeneration," said Reh, a neurobiologist at the University of Washington. "One reason we don't have more molecules we can test is that we don't have good animal models for many human retinal diseases."
Scientists will still need to overcome some serious hurdles before using the cells for transplantation therapies. The genetic flaws that led to the disease would need to be fixed before implanting the cells into the eye. And researchers need to figure out how to get large volumes of cells to integrate effectively into the retina. In the current experiments, published last month in the journal PLoS ONE, the number of cells that took root in the mouse eye was too low to restore visual sensitivity. "We need about 10,000 cells to integrate into the retina for them to restore function," Reh said.
Future research will have to explore how well the transplanted photoreceptors connect with other cell types in the retina and function as an integrated circuit. "The work still ahead is huge," said Robert Lanza, chief scientific officer at Advanced Cell Technology. "But this is a very important first step."
Photoreceptors created from induced pluripotent stem cells.
By Janelle Weaver
Think twice the next time you wipe a few flecks of dandruff from your shoulder. You might be shedding cells that may someday restore human vision.
Thomas Reh and colleagues at the University of Washington, in Seattle, have generated light-sensing retinal cells, called photoreceptors, from adult human skin cells. They then transplanted the cells into a mouse retina, showing that the photoreceptors integrated normally into the surrounding tissue. This technological feat raises hopes for the development of treatments for retinal diseases, such as retinitis pigmentosa and macular degeneration, which cause visual impairment or blindness in millions of people in the U.S.
Researchers used induced pluripotent stem (iPS) cell technology, activating a handful of genes in skin cells in order to revert them to a flexible embryonic state. They then used previously developed methods to differentiate the cells into photoreceptors. While Reh's team has done similar experiments using embryonic stem cells, iPS cells are a preferable source for cell replacement therapies because they can be derived from the patient. Skin cells are a ready source of cells that are tissue-matched to the recipient, bypassing problems associated with immune rejection of stem-cell transplants.
The cells also provide a new way to study retinal degeneration diseases and to identify drug targets. Retinitis pigmentosa, for example, is an inherited disorder in which the photoreceptors begin to die. Retinal cells derived from a patient with the disease harbor all the genetic mutations that contributed to the patient's disease, so scientists can try to determine the molecular mechanisms that lead to cell death. They can then use the cells to screen for molecules that can slow or stop the damage.
"There are no good drugs to slow photoreceptor degeneration," said Reh, a neurobiologist at the University of Washington. "One reason we don't have more molecules we can test is that we don't have good animal models for many human retinal diseases."
Scientists will still need to overcome some serious hurdles before using the cells for transplantation therapies. The genetic flaws that led to the disease would need to be fixed before implanting the cells into the eye. And researchers need to figure out how to get large volumes of cells to integrate effectively into the retina. In the current experiments, published last month in the journal PLoS ONE, the number of cells that took root in the mouse eye was too low to restore visual sensitivity. "We need about 10,000 cells to integrate into the retina for them to restore function," Reh said.
Future research will have to explore how well the transplanted photoreceptors connect with other cell types in the retina and function as an integrated circuit. "The work still ahead is huge," said Robert Lanza, chief scientific officer at Advanced Cell Technology. "But this is a very important first step."
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