There are three important things to know about the swim bladder of a fish. The first (and the only one relevant to the fish) is that it operates like the air tank of a submarine, enabling its owner to submerge and rise to the surface at will.
The second is that, when extracted, dried and turned into a powder known as isinglass, it filters out unwanted particles in beer and wine, rendering those beverages drinkable but also unsuitable for vegetarians (a fact not widely broadcast by brewers or vintners).
The swim bladder’s third application may be even more significant: it can heal wounds. Not just normal cuts and grazes, either, but the kinds of ulcerous and persistent lesions that defy conventional treatments for weeks, months and, in some cases, even years.
Sixty-six-year-old Maurice Parkinson from Southampton can attest to this. At the age of three, he suffered severe burns while playing beside an open fireplace.
“I received 75% burns to mainly my legs and the lower half of my body,” he recalls. “I spent two years at a hospital burns’ unit, undergoing plastic surgery to most of my body. I was given a life by Archibald McIndoe, the famous plastic surgeon who operated on me, as he had on so many badly-burnt fighter pilots in the second world war.”
At 51, Parkinson had to undergo skin graft repairs to his coccyx area for a persistent problem, and over a three-year period more recently he has had trouble with a split in his skin in precisely that area. The wound is about 30mm long by 30mm wide, but sometimes one or two other small holes appear in the area, with similar healing problems. “The wound can take six to nine months to heal, but this is only temporary, before it breaks down again,” he says.
Despite being told by two plastic surgeons there was nothing that could be done, determined Parkinson began an extensive course of reading, which led him to discover a method of wound treatment that was popular during the 18th century.
In a treatise in 1773, the scientist Humphrey Jackson describes the purification process performed by isinglass when placed in a large vat of beer, noting particularly how, mixed with malt liquor, the isinglass attracted what he called “curdly masses” in the ale, and carried them down to the very bottom of the barrel.
His study sparked off a boom in British-made isinglass; the footnotes to his report, in Volume 63 of the Royal Society’s Philosophical Transactions, record how some 40 tons of it were produced in response to his findings.
But the use of isinglass was not confined to making booze less lumpy. Having proved itself in the collection and removal of unwanted -material in alcohol, it was put to use in the treatment of infection in wounds. Before long, it came to be an essential ingredient in “court plaster,” so called because it was used by refined and wealthy folk.
Court plaster was the precursor of our -modern sticking plaster. Only instead of using strips of elasticated bandage, 18th-century physicians employed lengths of silk. And instead of antiseptic cream, they used isinglass.
More than two centuries later, it was used to treat Maurice Parkinson’s troublesome wound. Eventually.
“Over the years, I’ve tried many types of dressings,” he says. “Silver-impregnated dressings, foam dressings; I’ve even tried several types of air cushion to sit on, to alleviate pressure. However, after spending some time researching wound treatments throughout the world, I came to the conclusion that collagen dressings might be of some use.”
Which is where isinglass came in. The clue lies in the word “coller,” which is French for “to stick”.
Put simply, native intact collagen provides a natural framework, or matrix, for new tissue growth. What is more, the extraction process for isinglass preserves the crucial, triple-helical structure, which involves the entwining of the three polypeptide, or amino-acid chains that make up collagen.
As for the most suitable types of fish from which to extract the swim bladder, first choices are carp and sturgeon, followed by catfish. However, in 1795, a Scottish engineer called William Murdoch developed a cheaper version of isinglass made from dried cod.
Having read up on the benefits of piscean collagen, Parkinson needed to find a UK firm marketing it. After further investigation, he tracked down a small Bedfordshire firm called Medira, who source their collagen from Chennai in India. He began using their various dressings, which come in sheet, sponge and particle form.
After seven applications of the sponge dressing and two applications of the collagen particles, he found that the wound had healed over.
“I was both impressed and grateful,” says Parkinson. “For three long years, I had to wear various dressings and spend many long hours visiting clinics, doctors and surgeons. Yet this treatment took just eight weeks.”
And he is not the only UK patient to be indebted to isinglass. After an accident on holiday in Sardinia, which left her with a dislocated ankle and a fractured shin and calf, Leicestershire pensioner Maureen Gale developed an ulcer at the point where a securing screw had been fixed to her leg.
“I went to the clinic twice a week for two months but it just wouldn’t heal,” says Gale. “When the hospital asked if I’d try this fish--bladder treatment, I was ready to give anything a go,” she adds. “Within eight weeks, my ulcer had totally healed over.”
At the plastic surgery department in St Thomas’ Hospital, clinical nurse specialist Gaby de Luca has seen the value of use of fish-collagen dressings in a variety of wounds that don’t respond to conventional treatment.
“We’ve found a quicker healing rate than other, more basic wound dressings”, she says and, in a co-authored paper in The Diabetic Foot Journal, reports: “When applied topically, the collagen acts as a haemostat and helps to stimulate the growth of new tissue in the wound bed. This advanced wound care intervention has the potential to improve healing rates, reduce symptoms and improve quality of life while reducing long-term healthcare costs.”
An added advantage of fish-derived collagen is that it does not present the same cultural or religious problems as the collagen extracted from pigs or beef cattle. Or, for that matter, the potential for mad cow disease.
More important, though, is the way in which fish collagen particles can be applied to a wound, either in particle form or biodegradable sponge form, without the need for a dressing to hold them in place. This is a key factor when it comes to treating patients with a severe skin fragility disorder known as epidermolysis bullosa, or EB, which manifests itself in the form of open sores and wounds.
“Patients with severe forms of EB often display a fear of new products, as they fear they may adhere and cause pain and trauma on removal,” says a report by three clinical nurse specialists (two from Great Ormond Street Hospital and one from St John’s Institute of Dermatology in London). “The ability of Type I piscean products to biodegrade and therefore not require removal makes makes these products less threatening.”
Indeed, the result of a small-scale trial, using these biodegradable collagen treatments, showed that eight out of nine patients with severe EB, aged from six months to 41 years, showed measurable improvement or healing.
“Case studies conducted by my department have shown the effectiveness of piscean collagen dressings in the management of both adults and children with severe forms of EB,” says Jacqueline Denyer, one of the Great Ormond Street clinical nurse specialists. The results have demonstrated healing of wounds which have been present for several years, despite best practice and care at a specialised EB centre. “Additional benefits have been reduction in pain and bleeding and improvement in quality of life,” she adds.
Piscean collagen could be the way forward. Yet it takes more than scientific papers and anecdotal evidence to secure the official green light for a new course of treatment – even if it has been in use for the past 200 years.
At present, the isinglass issue is sitting in the equivalent of a pending tray, having been included on an NHS Commissioning Board catalogue “identifying emerging innovative thinking that may have the potential to form future programmes of work.”
The use of piscean collagen in Britain remains rather patchy, despite the efforts of Medira managing director, Roseanne Aitken. She estimates that treatment of a non-healing amputation wound takes 12 months and costs the NHS £16,000 – as against 10 weeks and £1,200 using her Helisorb particles, which contain piscean collagen.
“The benefits to this country could be huge, in terms of money saved and patient care improved,” she says. “At present though, my biggest customer is not the UK, but Greece.”