German researchers claim they have discovered a possible cause of Crohn's disease that refutes the long-held belief that it results from an overactive immune system. But while they are hailing it as a breakthrough, many others continue to be sceptical, writes Derek Scally in Berlin
German researchers say they have discovered a possible cause of Crohn's disease, the chronic intestinal disorder that affects more than one million people in Europe alone.
Researchers in Stuttgart and Heidelberg have proven that Crohn's sufferers lack a vital copy of a gene that makes their bodies produce smaller than normal amounts of a peptide called defensine, leaving their colon walls vulnerable to painful attacks by bacteria.
"A breakthrough like this only comes along once in a lifetime," says Prof Eduard Stange of the Robert Bosch hospital in Stuttgart.
"In the future, sufferers will be able to take a simple capsule to treat their condition."
His team has already registered a patent for their results in the US and have started down the path to a clinical trial and market release of a defensine medication for colon Crohn's within four to five years.
They are confident of doing the same for small intestine Crohn's, the other common form of the disorder.
Crohn's experts outside of Germany say the findings are important but are sceptical that supplementing sufferers' defensine will "cure" the disease. Nevertheless, a breakthrough would be welcome because while no one can agree on the causes of Crohn's, its effects are devastating.
First mentioned in the 18th century, Crohn's is named after the American gastroenterologist Burril Bernard Crohn, one of three researchers who published one of the first studies of the condition in 1932.
The German research team says their work is a decisive step in refuting the long-held belief in the scientific community over the past 30 years that Crohn's results from an overactive immune system.
"There's a 2.8 per cent mortality rate among Crohn's sufferers - the patients are dying because the treatment was eliminating their immune system and then they were picking up infections like tuberculosis and listeria," says Stange.
"The development costs for our treatment are around €20-€30 million, which is nothing compared to the billions wasted every year in false treatment."
But Crohn's sufferers, like all people with chronic conditions, are used to having their hopes raised and then dashed by researchers.
Suggested treatments in recent years have run the gamut from rheumatism medication to tapeworms. However, little makes its way on to the market, leaving doctors with no choice but to try to treat sufferers' symptoms rather than the disease itself.
"I live in the hope that they will have answers, but there have been so many miracle cures in the last 15 years," says Elizabeth Lattimore, honorary secretary of the Irish Society for Colitis and Crohn's disease (ISCC).
"When we do come to some real solution - and I'm optimistic that we will - there will be many factors: genetic, environment, even the food we're eating."
British Crohn's experts say the German research is novel and convincing, but they say it is more likely to be a modest contribution to fighting Crohn's rather than a stand-alone cure. "I wouldn't call it a major breakthrough," says Prof Tony Segal of the University College of London's department of medicine. "Without trying to be negative, there's been a lot of work on defensines in the past and none of it has borne fruit."
In February, Segal published his own paper in British medical journal the Lancet suggesting - similarly to the German team - that Crohn's is caused by a weakened rather than an overactive immune system, as previously thought.
Segal's team carried out experiments which showed that Crohn's sufferers produced much lower numbers of white blood cells called neutrophils to destroy bacteria that penetrate the intestinal wall.
The normally huge increase in blood flow to the infected area was markedly absent in Crohn's sufferers.
"Blood flow is an important part of getting cells to the problem. By increasing blood flow, we can get cells to an inflammation to gobble up the infection," says Segal.
"We are about to start a new trial to increase the inflammatory response using Viagra."
Exact numbers of Crohn's sufferers are difficult to come by, but the search for a cure for Crohn's is becoming more urgent as an increasing number of people in Western countries are diagnosed with the disease.
"We're even seeing diagnosis of Crohn's in very young children," says Lattimore.
British data show the incidence of Crohn's among people up to the age of 30 increased from 2.1 per 1,000 for those born in 1958 to 3.8 per 1,000 for those born in 1970.
[ www.iscc.ie ]