I watched CNN today while i was eating dinner. The main headline was about a woman having successfully replaced her trachea with an “artificially” grown one. Media calls this a fantastic turn point in medicine, and i agree, its certainly great news. But many news stations including CNN didn’t really know what they were talking about, the reason for this is the lack of preciseness regarding WHY its so great.
I will try to explain.
First i would like to mention that having a trachea with reduced structural strength is really a terrible thing. The reason for this is that the trachea can collapse during breathing causing a closing of the airways, what makes this scary is that the harder you try to breathe the harder the trachea collapse and the harder you choke. I must still emphasize that this relies on the amount of damage done to the trachea.
On Friday two weeks ago i came across a patient having exactly this, the anesthesiologist who led the ward “tour” was the attending doctor for this woman. She was an older woman having removed a tumor from her throat, as a result the trachea was so badly reduced that when she breathed it sounded like she was being choked by a 300 pound bodybuilder. The Dr. said when we were in the room that she is going to be put to sleep after we leave so they can intubate the patient to prevent her from choking. I hope you get an idea of how important the structure of the trachea is.
Now over to the news and the reason for why its great.
Our bodies are unique. not one single person is identical to the next (except identical twins) and one can easily tell by looking at the phenotypes of different persons like hair (colour and structure), height, skin colour etc. The reason for this uniqueness lies in the DNA, the DNA has one thing to do ( well lets keep it simple since dna can do more…), and that is to code for protein.
Now… Since we are all unique because of differences in DNA there are also differences in proteins… Proteins are the working heroes of our body, they do practically all the work, an example are nerve cells where ion-pumps (protein) cause a electric impulse to pass and making us able to hear, feel, see and smell.
Our immune system is also functional because of proteins, and this is why the stem-cell organ is so unique. Our immune system has some proteins wich can detect foreign particles and foreign proteins in our body, now if you transplant a random liver to a patient, you introduce an organ composed of cells from another body. Because of this the DNA in those cells differ from your dna (again… not if the donor is your identical twin). And since DNA codes for protein this means that some proteins are different from your own. The immune system does what its made to do and attacks the foreign proteins (the liver) causing a rejection of the organ and the organ loose its funtion and the patient dies. Now if one use the patients own cells this wont be a problem.
So whats up with STEM-cells?
Stem cells are special cells found in fetus and in the bone marrow of adults. These cells are cells that havent decided wether they want ot be a liver cell or a nerve cell, but once they specialize (called differentiation) they cant change again, so we cant use a liver cell to grow nerve cells. That is why stem cells are so much worth and so much discussed.
What docters did was that they took the trache of a deceased patient, stripped the trachea for cells, leaving only the cartilage left (the structure damaged in our needing patient). Then they added stem cells from the recieving patient and diefferentiated the cells to become “tracheal” cells by exposing the cells to a special serum, the cells then grew on the cartilage and made a new trachea wich could be implanted and with little or no risk of rejection. And this technique ia a worlds first.
THATS the great news.
As one can see, the trachea holds its form because of the cartilage.
