The Nobel Assembly at the Karolinska Institute in Stockholm, Sweden awarded the 2005 Nobel Prize for Physiology or Medicine to Dr. Barry J. Marshall, 54, and Dr. J. Robin Warren, 68, for their discovery of the Helicobacter pylori (H. pylori) bacterium and its role in gastritis and peptic ulcer disease. Up until their breakthrough in 1982, the long-held view was that spicy foods or stress caused ulcer disease.
According to information released by the Nobel Foundation, Dr. Robin Warren, a pathologist from Perth, Australia, observed small curved bacteria colonizing the lower part of the stomach in about 50% of patients who had their stomachs biopsied. He observed that signs of inflammation were always present in the gastric mucosa close to where he saw the bacteria.
Barry Marshall, a colleague, became interested in Warren’s findings and together they initiated a study of biopsies from 100 patients. Marshall succeeded in cultivating a previously unknown bacterial species – later named Helicobacter pylori – from several of these biopsies. They found that the organism was present in almost all patients with gastric inflammation, duodenal ulcer, or gastric ulcer. Based on these results, they proposed that this newly identified bacterium caused these diseases.
Until that time, so entrenched was the belief that lifestyle caused ulcers that, even with their evidence, it was difficult for these two researchers to convince the world of H. pylori’s role in ulcer disease. In fact, Alfred Nobel himself said in the late 19th century, “Worry is the stomach’s worst poison.” To provide even more conclusive evidence, in 1985 Marshall deliberately infected himself with the bacterium and established his own stomach illness.
Today, it has been firmly proven by many researchers world-wide that H. pylori causes more than 90% of duodenal ulcers and up to 80% of gastric ulcers. The remaining ulcers are usually a result of regular use of pain medications called non-steroidal anti-inflammatory drugs (NSAIDs), which includes aspirin and ibuprofen. Many people take NSAIDs to reduce pain and inflammation. Frequent or long-time use of NSAIDs, especially among older people, however, can increase a person’s risk of ulcer disease.
The H. pylori infection rate among adults in developing countries is well over 80% and it falls between 20-50% in industrialized countries. H. pylori infection is associated with an increased risk of developing gastric cancer, one of the most prevalent diseases world-wide.
A peptic ulcer is a sore or break in the lining of the digestive tract where gastric juices (acid and pepsin) are present. Most ulcers occur in the first part of the small intestine (duodenal ulcers) but they can also form in the stomach (gastric ulcers). About 10% of Canadians develop an ulcer at some time in their life.
When the H. pylori bacteria attach to the protective mucous coating of the stomach and duodenum, they weaken it, thus allowing acid to get through to the sensitive lining beneath. Both the acid and the bacteria irritate the lining and cause a sore, or ulcer, to form. At this time, it is unclear how these bacteria spread from person to person. It is also unknown why only a small percentage of people infected with H. pylori – only 10-15% – go on to develop peptic ulcers. Just because you have H. pylori present in your stomach does not mean you will get an ulcer, even though most people with ulcers are infected with H. pylori.
Ulcers are painful and, if left untreated can lead to severe complications including stomach perforation and bleeding.
There are several tests available to determine if a person has H. pylori infection: blood can be drawn and checked for evidence of antibodies to the bacteria; a special breath test can detect bacterial production of an enzyme in the stomach; or biopsies from the stomach can be examined for presence of the bacteria.
It is important for doctors to determine the cause of an ulcer before prescribing treatment. If NSAIDs have caused an ulcer, a doctor may recommend the patient stop taking the drug, perhaps suggest a different pain medication, or add other medications along with the NSAIDs to protect the stomach and duodenum.
If H. pylori infection is the cause of an ulcer, the doctor will prescribe a treatment plan to kill the infection and reduce the amount of stomach acid. This usually consists of a combination of one or more antibiotics to kill the bacteria, plus a proton pump inhibitor (PPI) to block stomach acid. When followed as prescribed, this treatment – usually called triple therapy – can permanently cure 80-90% of peptic ulcers. For the remaining 10-20% of resistant cases, quadruple therapy may be necessary, where other antibacterial medications are added.
It is advisable to treat H. pylori conservatively in patients without documented ulcer disease due to the risk that indiscriminate use of antibiotics to eradicate H. pylori from everyone, including healthy carriers, could lead to severe problems with bacterial resistance against these important drugs.
A natural product – cranberry juice – shows promise in preventing the bacteria from attaching to the stomach wall. H. pylori bacteria are present only in humans and have adapted to the stomach environment. The bacterium itself is extremely variable, and strains differ markedly in many aspects, such as adherence to the gastric mucosa and ability to provoke inflammation. Even in a single infected individual, not all H. pylori bacteria are identical and, during the course of chronic infection, these bacteria adapt to the changing conditions in the stomach. Genetic variations among humans may affect their susceptibility to H. pylori.
Many diseases in humans such as Crohn’s disease, ulcerative colitis, rheumatoid arthritis, and atherosclerosis are due to chronic inflammation. The discovery that one of the most common diseases of humanity – peptic ulcer disease – has a microbial cause has stimulated the search for microbes as possible causes of other chronic inflammatory conditions.
Even though no definite answers are at hand, recent data clearly suggests that a dysfunction in the recognition of microbial products by the human immune system can result in disease development. The discovery of Helicobacter pylori has led to an increased understanding of the connection between chronic infection, inflammation, and cancer. Definitely worthy of a Nobel Prize!