A research centre at University College Cork hopes to discover new drugs by studying the trillions of bugs in our digestive systems, reports Dick Ahlstrom
From "bugs to drugs" is the way University College Cork describes its new €16.5 million Alimentary Pharmabiotic Centre (APC). Dedicated to the study of the bacteria that colonise our digestive systems, discoveries at the centre could lead to new therapies for a range of persistent bowel diseases.
The APC, which officially opened last Friday, is the first of the new large-scale CSETs (Centre for Science, Engineering and Technology) to be funded by Science Foundation Ireland. The CSETs are major undertakings with the largest budgets yet made available for Irish research teams.
The centre received €16.5 million from SFI, plus funding from UCC-campus company Alimentary Health Ltd and international partner Procter and Gamble. It will examine the role being played by the complex bacterial flora in our digestive tracts, explains Prof Fergus Shanahan, director of the APC.
"In essence we are studying the interaction between bacteria in the gut and the host," says Shanahan, who is also professor and chair of UCC's Department of Medicine.
The Alien sci-fi films, where an alien invader takes up residence in a human host, have nothing on the teeming trillions of bugs that occupy our alimentary canals. The bacterial cell count is so high it outstrips the total number of humans that ever lived on this planet.
There are more bacterial cells than there are human cells in the body, adds Shanahan. In effect, the bacterial cells we carry about our person outnumber our own cells.
"We are 95 per cent bacterial in terms of overall cell count," says Shanahan. "These bacteria are often described as the hidden organ or the neglected organ of the body."
Taken together the bacterial cells in a single adult can weigh up to two kilos. "It is a living mass that is tantamount to a liver," he says. "When you think of its activity, it is equivalent to an organ. It has to be important."
Shanahan, with deputy director Prof Gerald Fitzgerald of UCC, will now try to discover just how important our bacterial hitchhikers actually are. Interest in them is not new, but the tools weren't available to really understand their biological significance, says Shanahan. "The difference now is having the technology to study it."
An APC team of 50 scientists and clinicians will gauge the bacterial influence on our gastrointestinal tracts and on our immune systems. Gut flora is essential in kick-starting our immune systems, and without them we would be in trouble, he explains. Researchers have raised "clean" mice that lack bacteria in their gut, and invariably they are unhealthy and more susceptible to illness.
The bugs also contribute directly to our ability to gain nutritionally from the food we eat. Our calorific intake would have to increase by a third without them, says Shanahan, because they help break down complex molecules. "They are net contributors to your body weight. They are not parasites, they are net contributors."
They can also produce negative effects, he adds. "They are clearly involved in disease, for example antibiotic-linked diarrhoea." Powerful antibiotics can disturb the bacterial balance, knocking out harmless species and allowing more pathogenic bacterial species to proliferate for a time. "They have a protective effect."
Of particular interest to the team is the ability of bacteria to produce their own antibiotics to hold overall numbers in check. "Their numbers are relatively stable. They signal to one another and produce bacterial antibiotics," says Shanahan. These same antibiotics could represent new types that could help against antibiotic resistance.
The team is also interested in the complex interplay between this bacterial environment and both an individual's immune system and genetic makeup. Discoveries in this area could help provide answers for the current rising tide of immune-related disorders associated with the gut.
Ironically, while both peptic ulcers and gastric cancer are in decline, the numbers of patients presenting with Crohn's disease, ulcerative colitis, gastroenteritis, food allergy, inflammatory bowel disease, bowel cancer and irritable bowel syndrome are all on the rise.
Some of these may arise from our personal interaction with the gut environment. It may be that alterations in gut flora could provide a trigger that initiates a disease state in the bowel.