Can stem cell
cure replace corneal
the future? Will this cure revolutionize the treatment for corneal blindness in
the world? An Indo-American duo is trying to unveil this major breakthrough.
The research on stem cell has found that the stem cells in eye possess the
ability to reinstate eye health even after getting affected by scarring or
whitening of the cornea that leads to blindness.
being spearheaded by Hyderabad-based Dr. Sayan Basu, consultant corneal surgeon
and scientist, L V Prasad Eye Institute (LVPEI)
and Prof. James L. Funderburgh of the University of Pittsburgh
School of Medicine in the US.
According to the research
scientist, curing the potentially blinding haze of a scar on the cornea may be
as simple as growing stem cells from a tiny biopsy of the undamaged eye of
patient and then placing them on the injury site.
In an exclusive interview with
Medindia, Dr. Sayan Basu talks about the research and how it is going to change
the lives of thousands of blind people.
1. Could you tell us about the experiment and the breakthrough
The cornea is the transparent front part of the eye and it covers the iris and pupil, and anterior
chamber, and it functions like a lens that allows the
light to enter and contributes to 65 - 75 percent of the eye's total focusing
power Therefore, damage to it lead to cloudiness or haziness that makes it hard or
impossible to see and the body usually responds to corneal injuries by making
an opaque scar tissue.
had previously developed a technique to obtain ocular stem cells from tiny
biopsies at the surface of the eye and a region between the cornea and sclera
known as the limbus. Removal of tissue from this region
heals rapidly with little discomfort and no disruption of vision.
After collecting biopsies from
banked human donor eyes, we expanded the numbers of cells in a culture plate
using human serum to nourish them. We conducted several tests to verify that
these cells were, in fact, corneal stem cells.
We then tested the human stem
cells in a mouse model of corneal injury. They used a gel of fibrin, a protein
found in blood clots that are commonly used as a surgical adhesive, to glue the
cells to the injury site. We found the scarred corneas of mice healed and
became clear again within four weeks of treatment, while those of untreated
mice remained clouded.
What are stem cells? Stem
are mother of all cells as they can divide and become any
specialized cell of the body. Their discovery has given modern medicine the
possibility of miraculous cure for most chronic diseases. However they are
still in the research phase and much of the work that is being done in various
labs of the world needs to be validated by others before they will be accepted
from for treatment.
such application is the eye is to treat corneal blindness that currently
requires corneal transplantation.
Could you give us latest details of the pilot-clinical trial?
clinical trial is intended to confirm that stromal stem cells can indeed be
isolated from tiny limbal biopsies in eyes of patients who have corneal scars
and that the procedure of isolating these cells refining them in the laboratory
and placing them back in the same eye is safe.
also trying to figure out the dosage of cells needed to achieve the desired
therapeutic effects. This pilot-clinical trial will also have a control arm
which will not receive any stem cells so that we can conclusively show what
difference the stem cells are making.
trial is being done on 5 patients in each group and all patients will be
followed for 6-months. We expect the trials to be completed by 2015. We
believe, the therapy would bring dramatic
reduction in blind people
When did you start this experiment? How did you get involved in this
scarring is a major cause of blindness in India. In fact most corneal
transplantations in our country are performed for this reason. However, the
waiting list for corneal transplantation
is very long as there are not enough eye banks in
our country to collect and store donated corneas.
are, according to recent estimates, 1-2 lakh (1,00,000- 2,00,000) people who
need corneal transplantations in India at present but only 10,000 to 30,000
transplantations take place every year. This huge gap in supply and demand
leads to further increase in the backlog and burden of corneal blindness.
corneal transplant surgeon, I believe that it is almost impossible to bridge
this gap by increasing Eye-banking infrastructure or by training more corneal
surgeons in our country. This is because corneal transplantation itself is not
the end of the story. People with transplants need life-long follow-up and
medical care. Many grafts reject and fail with time.
I have been interested in developing an alternative to corneal transplantation
that can address both limitations of this approach, namely, need for donor
tissue and risk of rejection. I believe that stem cell therapy holds the key to
solving the problem of corneal blindness in India and not corneal transplantation
and that we can achieve this by using the patients own stem cells. I have been
involved with basic scientists working on ocular stem cells since 2010 and have
been involved in this project since 2011.
you tell us more about the technique that is used to obtain ocular stem cells
from tiny biopsies?
The technique of retrieving cells
from the eye is known as limbal biopsy. Limbus is the area between the white
(sclera) and black (cornea) part of front of the eyeball.
In our study we described an
atraumatic method of obtaining a tiny biopsy from the limbal area, which can be
performed under topical anesthesia without requiring injections in the eye. The
limbal tissue is then transported to the laboratory where using the technique I
have developed the stromal cells are separated from the epithelial cells.
These cells are then purified
over several passages to yield a higher number of highly potent stromal stem
cells in a few of days. Then these cells are ready for transplantation. The technique
of transplantation is also completely novel and can be performed under topical
anesthesia and takes no more than a few minutes. In this technique the
superficial epithelial layer of the cornea is scraped off and the cells are
layered on the cornea over the scarred area as a gel. This is done by mixing
the cells in one of the liquid components of biological glue called fibrin glue
that is routinely used in ophthalmic surgery. As the gels with the stem cells
sticks to the cornea it is covered with a contact lens and the procedure is
Typically it takes no more than a
month for the cells to act on the corneal wound and render it completely
transparent. Patients will need only prophylactic antibiotics post-operatively
for a week when the contact lens is taken off. Since these are the patients'
own cells there is no need of long-term medications or risk of rejection. Also
since this technique requires no sutures, there are no suture related problems
6. How has your
association with Prof. James L. Funderburgh of the University of Pittsburgh
School of Medicine in the US helped in this experiment?
Professor James Funderburgh
discovered stem cells in the corneal stroma, which were capable of reversing
corneal opacification. We decided to work with him so that we could use his
expertise in this field to develop a stromal stem cell based method of treating
corneal blindness as an alternative to corneal transplantation.
I visited his laboratory in
Pittsburgh, USA and worked with him for one year between August 2012 and July
2013 as his research associate. Together we developed a minimally invasive way
of obtaining the stromal stem cells from human eyes. We also showed that these
cells have stem cell characteristics and are capable of restoring transparency
to an experimental model of wounded cornea. These results were published
The clinical implication of this research is
that we have established a reliable technique of isolating potent stromal stem
cells from human eyes that can be used to reverse and prevent corneal scarring
and furthermore that these cells can be obtained from the eyes of the patient
himself or herself. Thus there will be no need for donors or risk of rejections
because the stem cells could be obtained from the patients themselves.
About Dr. Sayan Basu: he is currently Consultant
Corneal Surgeon and Scientist at L V Prasad Eye Institute (LVPEI) in Hyderabad,
India. His research interests involve
developing stem cell based therapies for corneal diseases like corneal scarring
from infection or trauma. He performs about 300 corneal transplants every year.
He has over 40 international peer reviewed scientific publications and is also
on the editorial board of the British Journal of Ophthalmology. He did his
under-graduation and post-graduation from Kolkata in India.