Field of Science

Embryonic stem cells: can we really restore vision to the blind?


Restoring sight to the blind is, literally, a miracle.  For centuries, men have told stories of miracles in which a blind person suddenly was able to see again.

In modern times, there have been cases of vision restored thanks to corneal transplants and cataract surgery.  These are amazing treatments themselves, and they have become almost routine in the developed world.  But when the cells inside the eye are damaged, there is nothing we can do.

Until now.  In an amazing advance, scientists at Advanced Cell Technology reported this week in The Lancet that they used embryonic stem cells to restore partial vision to 2 patients who were legally blind.  One patient had macular degeneration, a very common but incurable eye disease, and the second had Stargardt disease.  Both diseases are progressive and usually lead to blindness.

Both diseases also affect internal eye cells known as retinal pigment epithelium (RPE) cells.  The research team, led by Robert Lanza, took human embryonic stem cells and coaxed them into becoming RPE cells.  They tested the RPE cells extensively for any signs of contamination by viruses or bacteria, and once they confirmed that the cell cultures were pure, they injected them into the eyes of these first two patients.  (Earlier studies were done in mice and rats before trying the therapy on humans.)

After four months, both patients showed improvements in vision.  This is an amazing result for macular degeneration, which has been, until now, irreversible.  The cells appeared to "take" in both patients, attaching to other cells in the eye and replacing damaged areas.  As Rob Stein and David Brown reported in the Washington Post
"One of them no longer needs a large magnifying glass to read and can reportedly thread a needle. The other has begun to go shopping on her own."
According to the study, neither patient has shown any signs of rejecting the cells.

The Lancet study, which you can read here, was funded entirely by private funds due to U.S. government restrictions on embryonic stem cell research.

This is only an early result from a very small study, but coming on the heels of reports just a few months ago, in which adult stem cells restored heart function to patients with advanced heart failure, the promise of stem cells again got just a bit brighter.

So yes, maybe we really can make the blind see again.

A surprising triumph in the fight against polio

Source: polioeradication.org
The last case of polio in India occurred exactly one year ago, on January 13, 2011.  In the decades-long battle against this devastating disease, this is one of the best pieces of news in a long time.  Just two years ago, health officials counted 741 polio infections in India, and it seemed that the battle was far from over.  It may yet be, but in 2010 the cases dropped dramatically, to just 42, and last year there was only one, on January 13.


As recently as the 1950s, polio was a dreaded, incurable disease that killed or paralyzed millions of children each year.  The U.S. alone had 58,000 cases in 1952. Then came the invention of a vaccine by Jonas Salk, one of the great medical breakthroughs of the 20th century.  By the 1960s, widespread vaccination campaigns had virtually eliminated polio from Europe and the U.S.  Polio lingered in the U.S., mainly in the Amish population who refused to accept vaccinations, but it finally disappeared in 1979.

The worldwide campaign to eliminate polio started in 1988, when 350,000 infections were recorded.  Polio is extremely difficult to control, because a large majority of infected people show no symptoms, but they can still spread the virus.  Vaccination campaigns need to treat everyone who comes in contact with an infected individual in order to break the cycle of transmission.  This is especially hard to do in remote areas of poor countries, especially when the populace is suspicious and uncooperative.

The greatest challenge in India came in the desperately poor, crowded regions of the north, where health care, hygiene, and education are all very poor.  The vaccination efforts were made even more difficult by conspiracy theories among the Muslim population.  As Simon Denyer wrote in the Washington Post this week:
"Rumors spread among the region's numerous Muslims that the polio vaccination campaign was an American conspiracy to wipe them out, by making their sons impotent and their daughters infertile.... Vaccinators were stoned as they approached Muslim neighborhoods. 'The general mind-set was that the immunization campaign was aimed at ending our lineage,' said Anwar Ahmad, the head of a madrassa in a Muslim neighborhood in the city of Meerut."
The campaign turned around after UNICEF and Rotary international launched a major education effort that first convinced Muslim leaders, and then everyone else, that the vaccine would benefit their communities.  With this success in India, polio is now endemic in only three countries in the world: Afghanistan, Pakistan, and Nigeria.  The same rumors and conspiracy theories that plagued India have spread within Muslim populations in these countries as well, but India shows that the misinformation - and polio - can be defeated.

Unfortunately, even here in the U.S. we have our own conspiracy theorists: the anti-vaccination zealots over at Age of Autism, where Dan Olmsted and Mark Blaxill recently posted a series of articles claiming that polio is "a harmless intestinal bug" that only causes disease when triggered by pesticides or by arsenic.  Never mind that there is no evidence to back this truly wacky assertion; these two anti-vaxxers seem happy to invent facts to support their single-minded campaign against all vaccines, even when the vaccines are demonstrably saving tens of thousands of lives.

Polio is still with us, and it could return.  Besides the 3 countries with endemic polio, 9 other countries continue to suffer polio cases that were imported from endemic countries.  Without widespread vaccination in those countries, polio could re-establish itself in any of them.

If polio stays out of India, we can thank the thousands of health care workers who traveled to remote villages, in extremely difficult conditions, to dispense lifesaving vaccines.  Their heroic efforts have paid off for everyone.  We should also thank the combined efforts of the WHOUNICEFRotary International, the Gates Foundation, and the CDC, all of whom are backing the worldwide effort to eradicate polio.  Let's root for humanity to win this one.