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Squalamine in the Daily Mail


http://www.dailymail.co.uk/health/article-2343533/Shark-pills-save-sight-grow-older.html

Eye drops made from sharks that may prevent you from losing your sight as you grow older

By Pat Hagan

PUBLISHED:18:44 EST, 17 June 2013| UPDATED:20:31 EST, 17 June 2013


Eye drops made from a chemical originally found in sharks' livers could help to prevent blindness.


The drops contain squalamine, a compound produced by sharks to stop them getting infections.


Now a synthetic version of the compound is being trialled as a treatment for age-related macular degeneration (AMD) - Britain's leading cause of blindness, affecting more than 500,000 people.


As well as warding off deadly viruses, squalamine is able to prevent the abnormal growth of blood vessels. It does this by blocking the release of growth factors produced by the body, which help blood vessels grow.



The compound that makes the pill was extracted from the liver of the dogfish shark after scientists started to investigate why sharks rarely get ill

Abnormal growth of blood vessels is one of the things that helps cancerous tumours thrive.


While research on squalamine as a cancer treatment is at an early stage, studies on its ability to prevent sight loss are advanced.


The growth of unwanted blood vessels at the back of the eye is also one of the major reasons for blindness in AMD.

There are drugs to treat the problem, but they have to be injected into the eye once a month in hospital. Drops can be administered once a day by patients.

The condition develops after the age of 50 and is caused by the growth of new blood vessels over the macula, a small oval-shaped area at the back of the eye that helps us pick out visual details.


These blood vessels tend to be fragile and thin-walled, which means they leak fluid that causes scar tissue to form, destroying vision in the centre of the eye.


This makes it difficult to recognise faces, read or watch TV.


Around 90 per cent of cases involve dry AMD, a form of the disease that comes on slowly over several years and for which there is no treatment.


The rest involve wet AMD - because of the leaking of fluid in the eye - which can cause blindness in just three months.




'Squalamine looked so promising after being used on 250 patients with wet AMD that it was fast-tracked for approval by the U.S. Food and Drug Administration.'




Treatment for the wet form involves injections into the back of the eye every four to eight weeks.


Given early enough, these drugs - designed to curb the growth of abnormal blood vessels - can help prevent complete loss of vision, but can't reverse the disease.


Drugs injected into the eye can slow down progression of the disease in 90 per cent of patients and can increase vision in a third.


Squalamine looked so promising after being used on 250 patients with wet AMD that it was fast-tracked for approval by the U.S. Food and Drug Administration.


The compound was extracted from the liver of the dogfish shark after scientists started to investigate why sharks rarely develop illnesses, but is now synthesised in a lab.


It's thought the chemical protects sharks from illness by preventing the growth of bacteria and viruses.


A study at Indiana University, published in the journal Retina, showed the chemical reduced neovascularisation - the growth of unwanted blood vessels - by a third.


It works primarily by blocking the effects of certain proteins that stimulate that growth. But at the time it was being given as a weekly infusion that had to be injected into the bloodstream.


The technique was effective, but was not very convenient and was unpopular with patients.


Now, though, New York firm OHR Pharmaceutical has turned the treatment into eye drops.


It is in phase two trials in the U.S., which means it is being tested for safety and effectiveness


Commenting on the technology, Professor Bernie Chang, honorary secretary of the Royal College of Ophthalmologists, said: 'This could be one of the most exciting developments in treating AMD.


'If it works as well as current drugs, it would mean patients would not have to come to hospital for injections into their eyes. But we need to be sure it works and does not have major side-effects.'