Monday, March 12, 2012

'Blood guardian' to prevent cardiovascular disease

In the circulatory system, a specific protein has been tasked with recognizing toxic compounds and enabling the body's defence system to cope with them. This protein, named pregnane X receptor (PXR), deals with harmful stuff coming from outside, but also a couple of things that are produced by the body itself. British researchers have discovered PXR has an additional feature: it protects against factors known to cause cardiovascular disease. The findings reveal we may possess a guardian in our blood vessels, that we can enable to prevent diseases.

PXR's main function is to switch on the production of detoxifying agents that need to break down whatever it is that is harming us. Toxic compounds accumulate in the liver, where various enzymes need to deal with them. Without the signals coming from PXR, the liver could get intoxicated, which does not bode well for our health. Because of its function in the liver it is also produced there, but British scientists found it to be present in blood vessels. It was already known the heart is also a healthy producer of PXR.

Culture of human tissue and blood vessels revealed PXR also plays a role in our circulatory system. What the scientists also found is that blood vessels, when given drugs stimulating the production of PXR, turned on several protective mechanisms. For starters, they turned on the production of antioxidants, which protect tissues from damage coming from certain chemicals known as free radicals. Secondly, several metabolising pathways were turned on, which is also beneficial to prevent disease.

Cardiovascular disease
In Western societies, diseases of cardiovascular origin are frequent killers. Blood vessels can get clotted because of unhealthy habits such as smoking and eating too much fatty foods. This mostly manifests as atherosclerosis, the most widely known form of cardiovascular disease. Damage to arterial walls due to free radicals, which can be produced by smoking, or fatty deposits and cholesterol can progress over time and end badly. Important arteries can be blocked, obstructing blood flow, or they get ruptured and cause internal bleeding. Turning on metabolising pathways in the blood vessels could be beneficial, because it would convert the fatty components to energy or non-harmful substances.
Atherosclerosis causes narrowing of artery walls, obstructing blood flow. This is caused by a placque, consisting of fatty deposits, cholesterol and other bad stuff. 
Atherosclerosis needs to be treated before it gets out of hand and kills the patient, but it would of course be better to just prevent it from starting or progressing. Not smoking and having a healthy diet and lifestyle would be the best way to start, but seeing as that will probably not work for a large part of the population judging from the obesity levels, enabling the body's protection mechanisms may be a more viable way. Because PXR is being produced and is functional in blood vessels, manipulating it in working more effectively could prevent cardiovascular diseases from developing. It does of course depend on whether we will be able to develop a therapy based on our newfound knowledge.