Stem cells bring sight to the blind in India
An eye institute in India has developed a way to grow new corneas from adult stem cells and restore sight to the blind.
(Fortune Magazine) -- Eye surgeon Virendar Sangwan has perfected a procedure so cutting-edge that most who have tried it have failed. In an operating theater in the central Indian city of Hyderabad, he surgically implants corneas grown in a petri dish from stem cells by his colleague Geeta Vemuganti in patients with damaged eyes. Together they perform about 80 corneal regeneration procedures a year, making the L.V. Prasad Eye Institute where they work one of the most prolific facilities in the world using stem cells to regenerate tissue of any kind.
The Sangwan-Vemuganti team uses stem cells found in the tissues of living adults, not ones derived from embryos. Teams all over the world are working with adult stem cells, trying to coax them to regrow cells in hearts, brains, livers, and other organs, but progress is slow.
Besides corneas, scientists have had some success regrowing skin cells and bone tissue, but those procedures remain experimental. "A number of programs around the world have tried to perfect this treatment, but they have had bad outcomes," says University of Cincinnati eye surgeon and stem cell specialist Edward Holland.
"It's impressive what they are doing at Prasad." In addition to the Hyderabad project, only Holland's program and a half-dozen others in the world conduct operations using corneas grown from stem cells.
The treatment uses stem cells harvested from the limbus, located where the cornea touches the white of the eye. For those with damaged corneas, these cells - called "limbic" and "conjunctiva" - are harvested from a patient's good eye, if he has one, or from a close relative.
They are placed in a petri dish and chemically tweaked to grow into the lower layer of a cornea, called the epithelium. It is then transplanted into the eye of the patient, where in most cases it takes hold and grows. In 56% of the cases at the Prasad Institute, patients could still see clearly 40 months later.
That is what 47-year-old Nuthalapati Partha Saradhi hopes will happen to him. In 1993 he was riding his motorbike with his wife through the nighttime streets of Hyderabad when someone jumped out of the shadows and threw acid at the couple. The chemical scalded a large swath of flesh on Saradhi's face, singeing his eyes and destroying both corneas. His wife suffered severe burns, but her eyes were uninjured. Saradhi spent 12 years as a blind man, undergoing multiple surgeries and skin grafts, until he heard about Sangwan's procedure.
The formerly blind Saradhi tears up when he recalls the day his bandages came off after his operation in 2005. "I immediately had back the vision - very clear vision," he says. The first thing he saw was Sangwan, then his brother, wife, and children, including his youngest, born after the attack.
"I cried for about ten minutes," he recalls. Sangwan was able to repair only one eye; the other was too badly burned, so Saradhi wears a glass eye, also made at the institute. "I am now able to drive a car," Saradhi says proudly, holding up his driver's license.
Indians are well known for reverse engineering, meaning they can deduce how drugs are made in order to produce generic versions. But in this case, Sangwan and Vemuganti, a pathologist, developed the technique on their own from reading papers and running experiments in the lab.
Sangwan says he had a number of patients with burned eyes who could not be helped with standard corneal transplants from cadavers, so he persuaded Vemuganti to try growing corneas in her lab. "You know how to grow cells, and I know how to do the transplant surgery," Vemuganti recalls him saying. "Why don't we work together?" She smiles and shakes her head. "I had no clue if this was going to work."
Vemuganti's major innovation was developing a platform on which to grow the corneas. First she designed a circular glass tube about the size of a stack of coins. "I had the handyman here cut the glass for me," she says. Then she overlaid the glass with tissue from a human placenta, which is "a good surface to grow the corneas on," she says. After that she placed stem cells in four places around a circle, added a growth medium, and watched the corneas begin to grow.
Founded in 1986, the Prasad Institute is named after the Bollywood producer who provided initial funding. The hospital performs 25,000 eye surgeries a year, ranging from cataract removal to LASIK procedures. The institute receives a small number of medical tourists from Europe and the U.S.; more come from the Middle East, Africa, and Asia.
A swank suite called the Pavilion serves wealthy patients, who pay five-star-hotel rates for rooms. Lower-income patients can receive the corneal procedure for free. The more affluent pay up to $1,500 - about one-tenth of what is charged in the U.S. for similar treatment.
Commercial interest among stem cell companies for the procedure has been scant because of the perceived small volume of patients, says venture capitalist Antoun Nabhan of Bay City Capital, who sits on the board of Cellerant, a leading stem cell company in San Carlos, Calif.
But corneal stem cell treatment may have wider applications, says ophthalmologist Ivan Schwab of the University of California at Davis. "These stem cells are similar to others in the body that make mucous membrane," he says. "These techniques of growing stem cells might one day be used to treat mucous-membrane tissue in the sinuses, bladder, and other organs."
For now, though, it's corneas that are making an enormous difference in the lives of blinded Indians. While Saradhi's face remains scarred with wine-colored stains from the skin grafts, in the midst of his damaged visage gleams a healthy eye, with a brown iris and a clear cornea no longer opaque and sightless. "I was very much happy. My children are so very much happy," he says. "It was a miracle."
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