Inflammation: An unsuspected killer. One in a series of posts discussing the impact of ten topics framed by ‘Insights of the Decade’ from the December 17, 2010 special issue of Science Magazine: Inflammation, climatology, tricks of light, alien planets, the microbiome, cell development, Martian water, the DNA time machine, cosmology and epigenetics.

Lists of a ‘top ten’ of anything are anathema to some people. The validity of such listing is usually questionable. Yet lists are undeniably popular. In this bewildering world of information at our fingertips, perhaps they are even necessary. We can’t think about everything but ‘top ten’ might be memorable. In any case, Science is one of the foremost science publications in the world. It’s an excellent source for a framework about significant work in the sciences. Unfortunately the original articles are now behind a paywall. They won’t be reproduced here, but their gist is present. I’ll try to put them in context and specifically within the Impact Areas of SciTechStory.

Almost everybody knows about inflammation. If you know about germs and you’ve cut yourself, you know that the cut can become infected. It becomes reddish, swollen – inflamed. Inflammation may be uncomfortable, but everyone knows that it’s the body fighting back, destroying the germs and helping the cut to heal. Inflammation is a good thing, so everybody thought.

A few doctors and scientists suspected otherwise. The symptoms of inflammation commonly associated with trauma or infection were not the whole story. They could see the symptoms in other medical conditions. One of the first was in a form of heart disease known as atherosclerosis, or hardening of the arteries. Atherosclerosis is a killer, one of the worst. In 1983 Russell Ross at the University of Washington (Seattle, USA) discovered macrophages, the white blood cells of the immune system, in atherosclerotic tissue. In short, the tissue looked like it was inflamed. During the next two decades evidence mounted: inflammation is an important component of atherosclerosis. That begs the question: What causes the inflammation?

A new study by a team at the Columbia University College of Dental Medicine (New York, USA) published in Volume 18 (January, 2011) of the Journal of Atherosclerosis and Thrombosis [Cultivation of Enterobacter Hormaechei from Human Atherosclerotic Tissue] indicates that a long suspected connection exists between atherosclerosis and the invasion of bacteria into arterial tissue. The bacteria may cause a chronic inflammatory condition that attracts plaque build-up – the known indicator of an atherosclerotic condition. Bacteria are everywhere in the human body, most of the time they don’t cause inflammation; so when they do, it’s an angle on disease that is both novel and promising for research and treatment.

In general, inflammation is symptomatic. It’s caused by something else, which means it shows up as paired with particular diseases. This is one reason why inflammation may have escaped the focus of investigation. For example, in various forms of cancer there is tissue damage, both within the tumor and often the surrounding tissues. Typically the body tries for tissue repair, and inflammation is part of the repair kit. Except the cure may not help, it may make the cancer worse by encouraging cell growth.

In other diseases, such as certain neuropathology and Type II diabetes, inflammation outright kills cells such as neurons and pancreatic beta cells that produce insulin. Inflammation also shows up in the fat of obese people. It’s not yet known why, although there is speculation that the immune system perceives fat cells as not normal and in need of repair. Is there some linkage between inflammation in the fat cells of obesity and the often obesity related appearance of Type II diabetes? Unknown, but it’s a question for which the correlations are tantalizing research.

Notice that inflammation is now associated with at least some kinds of heart disease, cancer, diabetes, Alzheimers and Parkinsons (the latter two in a murky fashion). This is the killer’s row of modern man, the most lethal diseases of civilized peoples. Thirty years ago inflammation was barely noticed with these killers. Don’t be surprised if in the coming decade there are important discoveries involving inflammation and major diseases.

SciTechStory Impact Area: Major Disease Cures