Biosynthetic Corneas Restore Vision in Humans

Biosynthetic Corneas Restore Vision in Humans

  10:26:00 AM    Science Lover

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A new study from researchers in Canada and Sweden has shown that biosynthetic corneas can help regenerate and repair damaged eye tissue and improve vision in humans. The results, from an early phase clinical trial with 10 patients, are published in the August 25th, 2010 issue of Science Translational Medicine.

Dr. May Griffith displays a biosynthetic cornea that can be implanted into the eye to repair damage and restore sight. (Credit: Photo courtesy of the Ottawa Hospital Research Institute)

"This study is important because it is the first to show that an artificially fabricated cornea can integrate with the human eye and stimulate regeneration," said senior author Dr. May Griffith of the Ottawa Hospital Research Institute, the University of Ottawa and Linköping University. "With further research, this approach could help restore sight to millions of people who are waiting for a donated human cornea for transplantation."

The cornea is a thin transparent layer of collagen and cells that acts as a window into the eyeball. It must be completely transparent to allow the light to enter and it also helps with focus. Globally, diseases that lead to clouding of the cornea represent the most common cause of blindness. More than a decade ago, Dr. Griffith and her colleagues began developing biosynthetic corneas in Ottawa, Canada, using collagen produced in the laboratory and moulded into the shape of a cornea. After extensive laboratory testing, Dr. Griffith began collaborating with Dr. Per Fagerholm, an eye surgeon at Linköping University in Sweden, to provide the first-in-human experience with biosynthetic cornea implantation.

Together, they initiated a clinical trial in 10 Swedish patients with advanced keratoconus or central corneal scarring. Each patient underwent surgery on one eye to remove damaged corneal tissue and replace it with the biosynthetic cornea, made from synthetically cross-linked recombinant human collagen. Over two years of follow-up, the researchers observed that cells and nerves from the patients' own corneas had grown into the implant, resulting in a "regenerated" cornea that resembled normal, healthy tissue. Patients did not experience any rejection reaction or require long-term immune suppression, which are serious side effects associated with the use of human donor tissue. The biosynthetic corneas also became sensitive to touch and began producing normal tears to keep the eye oxygenated. Vision improved in six of the ten patients, and after contact lens fitting, vision was comparable to conventional corneal transplantation with human donor tissue.

"We are very encouraged by these results and by the great potential of biosynthetic corneas," said Dr. Fagerholm. "Further biomaterial enhancements and modifications to the surgical technique are ongoing, and new studies are being planned that will extend the use of the biosynthetic cornea to a wider range of sight-threatening conditions requiring transplantation."

This research was supported by grants from the Canadian Stem Cell Network, the Swedish Research Council and County of Östergötland and a European Union Marie Curie International Fellowship. Initial work in developing the biosynthetic corneas was supported by the Natural Sciences and Engineering Research Council of Canada and the Canadian Institutes of Health Research. Recombinant human collagen type III used in formulating the biosynthetic corneas for the clinical study was provided by FibroGen, Inc., San Francisco, CA, U.S.A.

Dr. May Griffith is a Senior Scientist at the Ottawa Hospital Research Institute, Professor at the University of Ottawa (Faculty of Medicine) and Professor of Regenerative Medicine and Director of the Integrative Regenerative Medicine Centre at Linköping University. Dr. Per Fagerholm is a Professor of Ophthalmology at Linköping University. Dr. Neil Lagali is a senior lecturer at Linköping University. Other authors are listed in the paper.

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Stem Cells Cultured On Contact Lens Restore Sight In Patients With Blinding Corneal Disease

Stem Cells Cultured On Contact Lens Restore Sight In Patients With Blinding Corneal Disease

  8:12:00 PM    Science Lover

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In a world-first breakthrough, University of New South Wales (UNSW) medical researchers have used stem cells cultured on a simple contact lens to restore sight to sufferers of blinding corneal disease.

Dr. Di Girolamo and Dr. Watson.
(Credit: Image courtesy of University of New South Wales)

Sight was significantly improved within weeks of the procedure, which is simple, inexpensive and requires a minimal hospital stay.

The research team from UNSW’s School of Medical Sciences harvested stem cells from patients’ own eyes to rehabilitate the damaged cornea. The stem cells were cultured on a common therapeutic contact lens which was then placed onto the damaged cornea for 10 days, during which the cells were able to re-colonise the damaged eye surface.

While the novel procedure was used to rehabilitate damaged corneas, the researchers say it offers hope to people with a range of blinding eye conditions and could have applications in other organs.

A paper detailing the breakthrough appears in the journal Transplantation this week.

The trial was conducted on three patients; two with extensive corneal damage resulting from multiple surgeries to remove ocular melanomas, and one with the genetic eye condition aniridia. Other causes of cornea damage can include chemical or thermal burns, bacterial infection and chemotherapy.

“The procedure is totally simple and cheap,” said lead author of the study, UNSW’s Dr Nick Di Girolamo. “Unlike other techniques, it requires no foreign human or animal products, only the patient’s own serum, and is completely non-invasive.

The surgeon who carried out the procedure and managed the patients was UNSW senior lecturer, Dr Stephanie Watson.

"The operation is relatively non-invasive. The patient merely comes into the hospital for a couple of hours to have their eye prepared and the lens put in place, and then they're able to go home," she said.

“There’s no suturing, there is no major operation: all that’s involved is harvesting a minute amount – less than a millimeter – of tissue from the ocular surface,” said Dr Di Girolamo.

“If you’re going to be treating these sorts of diseases in third world countries all you need is the surgeon and a lab for cell culture. You don’t need any fancy equipment.”

Because the procedure uses the patient’s own stem cells harvested from their eye, it is ideal for sufferers of unilateral eye disease. However, it also works in patients who have had both eyes damaged, Dr Di Girolamo said.

“One of our patients had aniridia, a congenital condition affecting both eyes. In that case, instead of taking the stem cells from the other cornea, we took them from another part of the eye altogether – the conjunctiva – which also harbours stem cells.

“The stem cells were able to change from the conjunctival phenotype to a corneal phenotype after we put them onto the cornea. That’s the beauty of stem cells,” Dr Di Girolamo said.

The therapeutic contact lens used in the trial was of a type commonly used worldwide after ocular surface surgery. However, of the several brands on the market, only one was suitable for growing the stem cells.

“We don’t know why. It’s probably to do with the components the manufacturers have used in that particular lens,” Dr Di Girolamo said.

The researchers are hopeful the technique can be adapted for use in other parts of the eye, such as the retina, and even in other organs. “If we can do this procedure in the eye, I don’t see why it wouldn’t work in other major organs such as the skin, which behaves in a very similar way to the cornea,” Dr Di Girolamo said.

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‘Glue’ produced by shellfish may replace surgical stitches

‘Glue’ produced by shellfish may replace surgical stitches

  9:31:00 AM    Science Lover

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The new technology that will eliminate stitches could lead
to increased precision for exacting operations such as eye surgeries

Using the natural glue that marine mussels use to stick to rocks, and a slightly modified inkjet printer, a team of researchers from North Carolina State University in the US has devised a new way of making medical adhesives that could replace traditional sutures and result in faster healing, less scarring and increased precision for exacting operations such as eye surgery.

Sutures and synthetic adhesives have been in use for joining tissue together in the wake of a surgery.

Though sutures work well, they require enormous skill and longer operating times. Synthetic adhesives, though widely used, are the source of increasing concerns over their toxicological and environmental effects.

Since non-biodegradable synthetic medical adhesives do not break down in the body, they may lead to medical problems.

The new study shows that adhesive proteins found in the “glue” produced by marine mussels may be used in place of the synthetic adhesives without such concerns, as they are non-toxic and biodegradable.

Dr Roger Narayan, one of the authors of the study, says that the mussel proteins can be placed in solution and applied using inkjet technology to create customised medical adhesives, which may have a host of applications.

He thinks this approach may “significantly improve wound repair in eye surgery, wound closure and fracture fixation”.

“This is an improved way of joining tissues because the use of the inkjet technology gives you greater control over the placement of the adhesive. This helps ensure that the tissues are joined together in just the right spot, forming a better bond that leads to improved healing and less scarring,” Narayan says.

The researcher adds that this increased control would be a boon for surgery that relies on extreme precision, such as eye repair.

A research article on this study will appear in the Journal of Biomedical Materials Research B.

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Soon, a portable unit of surgical robots to replace army medics on battlefields

Soon, a portable unit of surgical robots to replace army medics on battlefields

  8:20:00 PM    Science Lover

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The Trauma Pod unit in action

Researchers in the US are working on a project that could replace army medics on a battlefield with robotic surgeons and nurses in the next 10 years.

The ‘Trauma Pod’ – being developed by US’ Defence Advanced Research Projects Agency (DARPA) - is currently undergoing trials.

Brendan Visser, a surgeon at Stanford University in California who helped develop the Trauma Pod, described it as: “Three separate robots dance over the top of the patient with their powerful arms moving very quickly, yet they don’t crash and they’re able to deliver very small items from one arm to another.”

The purpose of the Trauma Pod is to provide a quick “temporary fix” to wounded soldiers before being taken to the hospital.

“The system will focus on damage control surgery, which is the minimum necessary to stabilise someone. It could provide airway control, relieve life-threatening injuries such as a collapsed lung, or stop bleeding temporarily,” Pablo Garcia – of non-profit lab SRI International, which leads the project – told New Scientist magazine.

HOW IT WORKS

The Trauma Pod unit comprises one three-armed surgeon robot, assisted by 12 other robotic systems.

Remotely controlled by a human, the surgeon bot communicates with and instructs the other robots. One of its three arms holds an endoscope to allow the human controller to see inside the patient, while the other two grip surgical tools.

Garcia added that the robot could be allowed to carry out some simple tasks without human help, such as placing stitches or tying knots.

The bed itself monitors vital signs, administers fluids and oxygen, and may eventually administer anaesthesia.

A voice-activated robotic arm “Hot Lips” - derived from the nickname of a nurse in the TV series M*A*S*H - passes fresh tools and supplies to the surgeon bot. A third “circulating nurse” robot gives out the right tools.

The Trauma Pod unit recently passed the first phase of a feasibility trial, where robots treated a mannequin with bullet injuries by inserting a plastic tube into a damaged blood vessel and operating to close a perforated bowel.

The team hopes to eventually shrink the Trauma Pod to a collapsible unit encased in a portable shell that can be carried on the back of a vehicle.

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