British scientists have managed to grow new heart valves by taking stem cells from adult bone marrow, coaxing them to turn into heart valve cells, and then growing them into heart valves. The experimental valves were placed into animals, and so far they worked.

Heart valves are sometimes harmed by Rheumatic fever following a strep throat, or by infection. In other cases, they are abnormal from birth, but may not begin to cause problems until the person is an adult.

Now, there are four valves in the heart but there are two types of heart valves, and most of the articles did not say which valve was grown, but this article give the information that it was the aortic valve. It also has some nice photos of the newly manufactured vavle which you can compare to the photo below.
The aortic valve is the one that, after the heart squeezes out the blood, keeps the blood from dropping back into the heart. It is a delicate valve, quite thin. Usually there are three “leaflets” that close, but a lot of people are born with two valves. Others have the valve injured by infection or rheumatic fever.

When the valve is damaged, the valve either leaking or partly stuck together so it doesn’t open completely. The doctor will hear a “whoosh” to let him or her know that there is a problem, and then we often do an ultrasound to check how badly it is blocked. Usually a person does well until the heart just can’t do all that hard work of pumping and the patient develops Angina (heart pain) or shortness of breath from pump failure (Congestive Heart failure). Then you have to fix it in a hurry, because the patient goes down hill quickly.

This gets complicated, but once you decide on surgery, you have two choices: Mechanical or pig.

The pig valve lasts only about 10 years before it wears out and you need another operation. So why do it? Well, the main reason is that the mechanical valve gets coated with platelets and forms small clots…if these break off and go to the brain, you end up with a stroke. So the mechanical valve means you have to take blood thinner, which means constant blood tests to check the dosage is okay, and the danger of bleeding if the blood gets too thin. And bleeding problems are a major problem for those whose profession involves strenuous activity.

For example, Arnold Schwartzenegger originally had a pig valve replacement of his valve because he was born with a “bicuspid” valve. But the valve failed and he ended up with a regular mechanical valve. Since this made “action movies” risky, he decided to change to an easier job and became governor…Don’t like Arnold”?? it’s the pig’s fault.

The mechanical valve, however, lasts probably twenty years. They are usually reliable, the first ones being place back in the late 1960’s. There are a lot of variations, but the “oldie but goodie” are a simple basket with a ball that flops back and forth.Often the wires are now coated to stop blood clots from forming, and other variations are discs instead of balls, but this is the most common type we see.

They are noisy, and one of my patients told me that her grandkids liked to listen to the clicks in a quiet room.

The hope of the stem cell valve is that it will last longer than the pig valve, and won’t have the danger of taking blood thinner medicine.

Finally, you notice I added “bone marrow stem cells” to the original headline.
Yup. Another success from ADULT stem cells.

The dirty little secret about the hype for embyonic stem cells (mainly by companies who can’t get private investors to fund their research) ignores that there already have been many treatments from Adult stem cells, which are cheaper, more abundant, and have no ethical problems of destroying life or of exploiting poor women to obtain eggs.


Nancy Reyes is a retired physician living in the rural Philippines. Her webpage is Finest Kind Clinic and Fishmarket, and she posts medical essays on HeyDoc xanga blog.

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