August 3, 2010

Regeneration of organs, limbs, not solely fiction now

Science has made many strides in the field of medicine, but now it is delving into what we had once though to be science fiction and only for Canadian born super-heroes.

In general cell generation is limited. Cells take time to divide, and cannot be reprogrammed to form other biological machinery. The skin cells cannot regrow bone, kidney cells cannot regrow a lung, and so on. The ability to regrow a limb in the multicelluar animal kingdom is limited to certain types of lizards, (and only their tale) as well as worms. Once a cell is programmed to preform a certain function (which is decided fairly early on in life) it thus far can't be reprogrammed to form new tissue.

That's starting to change....

The first instance I'll talk about is about joint replacement. Today's titanium joints work fairly well, but need to be replaced after about 10 years. Replacing them, however, is a challenge for both the patient and the surgeon and often involves weeks of rehabilitation. A team from Columbia University has proposed a way to deal with this problem: inserting a chemical-infused scaffold generates new tissue by attracting stem cells. The scaffolding, meant to resemble a joint, was infused with growth horomone to encourage cell generation in several rabbits. Thanks to the added growth factor protein, the rabbit's own stem cells naturally migrated into the scaffold and regenerated both the cartilage and the bone beneath it. The surgery to replace the joint is similar to now, except there would be no need to go back into the patient, as the joint would be natural. This is a good proof of concept in order for future regeneration of boneloss. However young rabbits are already well known for their ability to heal, and what rabbits that received the scaffold without the chemical only healed somewhat. Growth horomone while natural can lead to complications in older patients, so it would need to be monitored...

Regardless however, it is a solid proof of concept that this indeed can work and that a patient's own body can heal itself, given the right tools. This would be a marked improvement over prostetics and synthetic limb growth both of which hold the possibility of the patient's body rejecting the new limb.

Every adult creature still has stem cells, but they grow in limited numbers and are typically found in the bone marrow and therefore later in the blood, younger creatures tend to have more of them, as their bodies are still growing. Unlike other cells they may differentiate and change their function (lung cell, heart cell etc...). Stem cell research has had some bad press due to it's use of fetal stem cells, but there is a greater use of adult stem cells, which poses less ethical quandries. Stem cell research opens up alot of possibilities for future medical advances.

Meanwhile over at Yale great strides are being made in the field of organ growth. In a way similar to the one above, a scaffolding of a lung was used and then was implanted with stem cells, which then regrew the lung. It was not perfect however, as the newly formed lung did seem prone to blood clots. The organ was not reconstructed from the mouse's own tissue as well so it was prone to being rejected as a foreign substance by the body as well. It was reported that great stem cell research would be necessary before this would be applicable for use on a human.

There's alot of promising technology in the offing... it still needs work however

My love of science fiction is quickly being overshadowed by the fact that the world is BECOMING science fiction.

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