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Friday, 28 November 2008

Organs without limits

In today's edition:

  1. Can an Artificial Heart Replace the Real Thing?
  2. Scientists coax brain cells in mice to regenerate
  3. 'Anti-Aging' Pill Makes Mice Mighty
Amazing news, just for you. This is a very optimistic edition. Do you realise we may be the last generation to die or the first to live forever? Or at least much more! This is so magnificent.

Can an Artificial Heart Replace the Real Thing?

Working with the European Aeronautics Defense & Space (EADS) French researchers have developed a pioneering new artificial heart. Dr. Alain Carpentier, the heart surgeon who led the development of the device, said that the first heart patients may receive the experimental organ in just three years.

Its developers say the new heart is the closest thing yet to the human body's natural ticker. The new device employs two pumps, instead of one, more accurately mimicking the function of a real heart's two ventricles, as well as a system of miniature sensors that react to physical activity and automatically increase or decrease the heart rate and blood pressure. The prosthesis also uses new composite bio-tech materials, which are made from animal tissue and chemically treated to eliminate the risk of blood clots, Carpentier says, a problem that has plagued earlier alternatives.

That's good news for the estimated 20,000 people worldwide who are each year in urgent need of a heart transplant for survival. Currently, only about a quarter of those patients receive transplanted hearts from donors. The first transplant patients will likely be the critically ill, who currently receive existing artificial hearts as end-of-life treatments, but Carpentier expects his new heart to be tested increasingly in younger heart patients.

So far, the Carmat heart has been tested in the lab and in animals; it could take up to two years to get the approval needed to begin human trials. Among the issues that still need to be worked out: battery life. One charge, for example, runs anywhere from five to 16 hours (compared to 30 minutes on rival).

If the heart proves safe it's expected to hit the market with a $250,000 price tag. source

My comment: Awesome! Seriously, the need of artificial heart is obvious-so many people die without ever getting a transplant, or waiting for it. Now, at least unnecessary waste of human life can be saved. Though, it sounds somewhat disgusting that the heart is made out of animals tissue, still, it will work. I just wonder how much of a pressure it can stand, because the normal heart is pretty tough in this.

Scientists coax brain cells in mice to regenerate

(Reuters) – Scientists have found a way to get damaged nerve cells in the brains of mice to repair themselves, a finding that may lead to new treatments for spinal cord and brain injuries.

By turning off proteins that keep nerve cell growth in check, the researchers were able to stimulate regrowth in mice with damaged optic nerves, they reported on Thursday.

A separate team found that blocking a protein that discourages cell repairs allowed nerve cells in lab dishes to regenerate.

Taken together, the findings offer leads on ways to coax damaged nerves in the brain and spinal cord to fix themselves.

The studies focused on nerve fibers called axons that carry electrical signals throughout the body.Unlike fibers in arms and legs which recover, brain and spinal cord nerve fibers do not regenerate.

Nerve injury shut down a gene network called mTOR pathway(and active in our youth) completely. Two proteins -- PTEN and TSC1 -- appear to be responsible for silencing this pathway, the researchers discovered. If they are suppressed, the neurons regrow.

Mice genetically engineered to lack the proteins kept more neurons after an injury to the optic nerve than normal mice. And the mutant mice were able to grow new axons within two weeks. The team is now looking for drugs that can block the proteins.

Tessier-Lavigne and colleagues focused on a different problem -- the chemicals in the body that discourage repairs. When an axon in the spinal cord is severed, the cut end sprouts a growth cone.

Tiny sensors on the growth cone pick up chemical signals. In nerves in the periphery of the body such as the finger, signals tell the axon to repair itself. But in the central nervous system, chemical signals repress growth.

Tessier-Lavigne's team found one of those signals -- a protein called PirB -- in the insulating myelin sheath that wraps around each neuron. When they blocked this myelin protein in cell cultures, they got nerve cells to grow. source

My comment: Apart from the great discoveries that obviously give great hope to people that suffer neural damages, one thing impresses me. Why the not-important neural paths recover and the important ones don't? That's very odd, since it doesn't give any biological advantage to the organism. For me, finding out why this happens is very important. It could give us such a deep understanding of our body.

'Anti-Aging' Pill Makes Mice Mighty

Nov. 7, 2008 -- Eat more than you should. Stay skinny. Run twice as far. Those are the big claims coming from a new drug study from Sirtris Pharmaceuticals, Inc., based in Cambridge, Mass. This latest study clears the way for human clinical trials of SRT1720, often touted as an "anti-aging pill."

SRT1720 activates the same receptor as the much-discussed resveratrol, the chemical in red wine that may slow some effects of aging. Both resveratrol and SRT1720 are being tested as a way to treat type-two diabetes first, and possibly other age-related diseases, later.

The European scientists overfed two groups of mice by about 40 percent. For a person, that would be close to eating 3,000 calories a day, enough to pack on significant weight.

The mice were first divided into a control group and test group. The test group was given two doses of SIRT1720: 100 mg or 500 mg.

After 15 weeks of eating the high-calorie diet, the control mice gained significant weight. The mice taking 500 mg of the drug, however, gained no weight. The cholesterol levels of the mice on the drug also improved.

The animals' exercise habits were also recorded. Mice without SRT1720 ran for roughly half a mile. Mice given 100 mg ran roughly seven-tenths of a mile. And mice on 500 mg of SRT1720 were able to run a full mile, twice the distance of untreated mice.

Dipp won't speculate on the drug's upper limits, other than to say that tests have shown that above 500 mg, its effects plateau. SRT1720 has no known side effects.

The research, led by Johan Auwerx at the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, was published this week in the journal Cell Metabolism.

SRT1720 is about 1,000 times more powerful that resveratrol, say the researchers. The two chemicals are not related structurally, but both influence the same chemical pathway in the body -- in particular, a type of receptor called SIRT1.

SRT1720 is more powerful than resveratrol because the body doesn't break the drug apart as quickly as it does resveratrol, making it more efficient at binding to the receptors.

The SIRT1 receptor is also activated during caloric restriction diets, which have been shown to lengthen life span in multiple animal models, and during exercise.

SIRT1 receptors are found in mitochondria, often called the powerhouse of the cell because of all the energy they produce.

SRT1720 would be used as a therapeutic drug, not a preventative measure. "The FDA doesn't have a clear approval path for disease prevention," said Dipp. "It does have paths for treating disease, however, and that's what we are going after."source

My comment: Now, two points. First, the fact that they made that research and it worked is amazing. I have a lot of faith in that drug, although I kind of prefer to stick to red wine for the moment. But just notice the last paragraph-FDA doesn't have a prevention path. Does it mean it won't allow it as a supplement? I doubt, but it sounds like this! I'm glad the research is European, that makes me so proud!

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