Science and Reason: Some causes of atherosclerosis

There is a certain sort of person who likes to find a single, simple cause behind diverse phenomena. For instance, regarding disease, such a person likes to view it as preponderantly the result of poor nutrition, pollution, pesticides, infections (bacterial, viral, or both), lack of antioxidants in the diet to quench "free radical cascades", negative thoughts, or whatever.

Sometimes, evidence even comes along that, surprisingly, fingers a favored disease mechanism that most observers had not suspected. For instance, stomach ulcers, long believed to be due to "stress" and "anxiety", have turned out actually to be caused by a bacterium, Helicobacter pylori.

Although such simplistic views of disease etiology tend to be wrong in general, new cases continue to turn up, as we learn more, where the simple theory does work. (Or, at least, it is a factor, since many if not most diseases can have multiple "causes".) Infection, by bacteria, viruses, or other parasites, is a frequent example.

Here are two recent instances, both involving atherosclerosis:

Cytomegalovirus exacerbates atherosclerosis through an autoimmune mechanism

A new study conducted by researchers from the University of Verona and the Institute G. Gaslini in Genova, Italy, confirms the pivotal role played by Cytomegalovirus infection in the pathogenesis of atherosclerosis.

Atherosclerosis is the main cause of morbidity and mortality worldwide. Classic risk factors including smoking, diabetes, hypertension and high cholesterol levels are known to play a pivotal role in the pathogenesis of the disease that also recognises a genetic influence. However, it is well known that acute cardiovascular events may happen without the presence of the mentioned common risk factors. Recently inflammation and infectious agents have been shown to play an important role in the onset of acute cardiovascular events.

Bacterial Infection May Contribute To Cardiovascular Disease

A new dissertation shows that Chlamydia pneumoniae can contribute to cardiovascular disease. Half of the population of Swedish twenty-year-olds are carriers of the bacterium Chlamydia pneumoniae, an ubiquitous pathogen previously known to cause acute respiratory disease. It now appears that this bacterium also contributes to cardiovascular disease, the single greatest killer disease in the western world.

In a new thesis in the field of pharmacology, Hanna Kälvegren demonstrates that the respiratory bacterium Chlamydia pneumoniae stimulates the process that leads to hardening of the arteries. This in turn causes heart attacks and stroke, by increasing the risk of thrombus, or blood clots.