Green tea may eventually be used in… surgery

Although naturopathic medicine is not simply the use of natural alternatives to drugs and surgery, I found an interesting article that considered the use of a green tea phytochemical in a surgical procedure.

For patients who have coronary artery disease and plaque build up in their arteries, a rupture of a plaque can cause clotting and may culminate in a heart attack. The medical options at this stage involve the use of “clot-busting” drugs such as streptokinase or tissue plasminogen activator, and the surgical options may involve the placement of a stent to open the artery or bypass surgery. The placement of a stent sometimes is used for patients at high-risk of having a heart attack, who may have proven severe blockages in their arteries.

The above picture shows a stent that has been placed to “open” an artery and restore blood flow. Here’s the problem – very shortly after, sometimes within a couple of years, the stent can re-occlude and thus narrow the blood flow again.

This led to the use of drug-eluting stents. The stents would be placed but would be designed to slowly release drugs such as clopidogrel, which in theory would prevent clots and fibrin from sticking to the stent and blocking the artery again. Problem is, side-effects from the drugs often were a problem, including excessive bleeding.

Researchers in Kyoto University might have had an epiphany while sipping green tea that the known protective effects of tea against heart disease and cancer might be useful in keeping stents open after they have cleared an artery. They published in Biomaterials (Epub Nov 2007) on their research of using the active ingredient in tea, epigallocatechin gallate, as a coating on stents.

The results?

“E-PLCL significantly suppressed the migration and invasion of VSMCs as well as the adhesion and activation of platelets. E-PLCL coatings were able to smooth the surface of bare stents with neither cracks nor webbings after balloon expansion. “

In other words, smooth muscle cells did not start to block the stent, platelets did not start the clot process on the stent, and the stent stayed nice and smooth.

Is this all a moot point? Perhaps having lots of green tea as part of a healthy diet may have prevented a coronary artery disease patient from having to get the stent placed in the first place. Maybe chelation or plaquex would have prevented it.

It might be that you have to drink green tea frequently, the way it is consumed as an all day beverage in China, to get its best benefits in cardiovascular disease. A recent study in the Journal of the American College of Nutrition (April 2007) showed that EGCG at 300 mg (about 4 cups of matcha tea, or 8 cups of chinese green tea) improved endothelial function short term (2 hours after the dose). Results were back to normal after 14 hours, even after 2 weeks of consistent dosing. Improved endothelial function basically means the lining of the arteries is more stable, and produces chemicals such as nitric oxide to relax and dilate the blood vessel. This is extremely important as a 10% dilation in the blood vessel effectively doubles the amount of blood passing through.

Another mechanism of green tea, or particularly EGCG (epigallocatechin gallate) in the green tea, is that it may condition and exercise the cells. Too frequently, it is called a super anti-oxidant. Like it’s phytochemical friend resveratrol from wine and grapes, EGCG protects heart muscle from something called ischemia-reperfusion. Ischemia-reperfusion is the process that often damages and kills heart muscle if it has been deprived from oxygen for a short time, and then reperfused with oxygen. EGCG and resveratrol drastically cut down the death rate after ischemia-reperfusion. Some would say that this shows EGCG protects the heart by being an antioxidant.

In reality, EGCG stimulates oxygen utilization at the cellular level, so that the cells are used to increased oxygen consumption and thus have defenses in place. See the resveratrol post for more information.

My favorite green tea? It switches between matcha tea (the powdered green tea used in Japanese ceremonies) and Dragonwell chinese tea. There is more theanine in the matcha tea, and more caffeine, so for the combination of alertness and calmness, matcha is hard to beat. Dragonwell (long jiang) is great for its flavor though.