The connecting theme is inflammation. Inflammation is associated with many diseases, from Alzheimer’s disease, to diabetes, arthritis and strokes. Inflammation is a general term of the ‘switching on’ of the body’s immune system. Here white blood cells are sent to fight potential infectious agents. However, once activated the immune system is hard to switch off and it can sometimes go out of control and cause damage to other parts of the body. This ‘self-inflicted’ damage is seen as the trigger for the various ill-health conditions.
Examples of immune system damage include overactive blood clotting, excessive levels of iron in the blood, and sheets of abnormally folded proteins. It seems that bacteria may have a role in all of this, by triggering the immune system. This is the view of Professor Douglas Kell of the University of Manchester, U.K., and Professor Resia Pretorius, from the University of Pretoria in South Africa.
Blood was once thought to be generally free from bacteria or, at least when an infection occurs, for bacteria not to survive. This was based on culture based microbiology which requires bacteria to grow on a culture medium. It’s now known that many bacteria are unculturable (through DNA studies). With blood, current evidence suggests that each milliliter of blood probably contains around 1000 bacterial cells.
Many types of bacteria secrete a cellular substance called lipopolysaccharide (or ‘endotoxin complex‘). This stimulates the immune system into action. This effect has been replicated, New Scientist reports, by taking bacteria from the gut and mixing them with the types of blood proteins (like fibrinogen) found in the human body. These studies confirmed that the presence of the bacterial proteins was sufficient to activate the immune system — even though there was nothing directly for the immune system to work against.
The data suggests that bacteria, in certain conditions, can activate an immune response; the body’s immune system is then left to ‘run free’ without any direct threat and this, in turn, causes potential damage. The damage might lead to certain diseases occurring. This finding is likely to trigger further research.
The findings to date are published in the Journal of the Royal Society Interface. The paper is titled “Acute induction of anomalous and amyloidogenic blood clotting by molecular amplification of highly substoichiometric levels of bacterial lipopolysaccharide.”
