STROKE and Your OWN STEM CELLS

"Every five minutes someone in the UK has a stroke and it is vital that we do all we can to help those affected by stroke."

Wise words from a team of wise scientists in the UK that pushed effective stem cell treatment for strokes a significant step forward as they revealed in their work is published in the Journal Biomaterials how they have replaced stroke-damaged brain tissue in rats.

The team of scientists is funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and led by Dr Mike Modo of the Institute of Psychiatry, King's College London. The work, carried out at the Institute of Psychiatry and University of Nottingham, shows that by inserting tiny scaffolding with stem cells attached, it is possible to fill a hole left by stroke damage with brand new brain tissue within 7 days. Previous experiments where stem cells have been injected into the void left by stroke damage have had some success in improving outcomes in rats.

The problem is that in the damaged area there is no structural support for the stem cells and so they tend to migrate into the surrounding healthy tissues rather than filling up the hole left by the stroke.

Dr Modo said: "We would expect to see a much better improvement in the outcome after a stroke if we can fully replace the lost brain tissue, and that is what we have been able to do with our technique."

Using individual particles of a biodegradable polymer called PLGA that have been loaded with neural stem cells, the team of scientists have filled stroke cavities with stem cells on a ready-made support structure.

Dr Modo continued: "This works really well because the stem cell-loaded PLGA particles can be injected through a very fine needle and then adopt the precise shape of the cavity. In this process the cells fill the cavity and can make connections with other cells, which helps to establish the tissue. (picture)

"Over a few days we can see cells migrating along the scaffold particles and forming a primitive brain tissue that interacts with the host brain. Gradually the particles biodegrade leaving more gaps and conduits for tissue, fibres and blood vessels to move into."

The research published today uses an MRI scanner to pinpoint precisely the right place to inject the scaffold-cell structure. MRI is also used to monitor the development of the new brain tissue over time.

The next stage of the research will be to include a factor called VEGF with the particles. VEGF will encourage blood vessels to enter the new tissue.
Professor Douglas Kell, BBSRC Chief Executive said: "Stroke is a leading cause of disability in industrialised countries. It is reassuring to know that the technology for treating stroke by repairing brain damage is getting ever closer to translation into the clinic.

This crucial groundwork by Dr Modo and his colleagues will surely be a solid foundation of basic research for much better treatments in the future. Joe Korner, Director of Communications at The Stroke Association commented: "This research is another step towards using stem cell therapy in treating and reversing the brain damage caused by stroke. It is exciting because researchers have shown they are able to overcome some of the many challenges in translating the potential of using stem cells into reality."

The potential to reverse the disabling effects of stroke seems to have been proved. However the development of stem cell therapy for stroke survivors is still in the early stages and much more research will be needed before it can be tested in humans or used in practice.

Bioengineering like the movies: Stem Cell Capturing Gadget

I'd hate to sound as if I was brought up on an entertainment diet of Hollywood movies, but back in the 1970's to 80's there was a real revolution in cinematic production and audience interest that led to a cult following of the science fiction genre.

Film directors often take what's probable in science and stretch them to the limits of our imagination, engaging us to just reflect on not only how far we've come but also how much further we can aspire. This next entry is a tribute to the 1987 movie "Inner Space"*.




In a recent announcement, MIT's bioengineers have designed an implantable device that is capable of capturing pure samples of stem cells from the circulating blood. The device is described as "a length of plastic tubing coated with proteins" which has been experimentally implanted into the bloodstream of rats.

The more accurate medical description of this plastic tubing is known as a "shunt" and the method of implantation would most likely involve the severance and reconnection of a small but high through-flow blood vessel. The proteins -known as selectins- attract and trap specific cells with the right signals on the surface (imagine a sticky mat). The cell capture devices are developed by chemical engineers led by Associate Professor Michael King from the Biomedical Engineering department at the University of Rochester. The technical details will be described in the March edition of the British Journal of Hematology.

(personal note: Mr. B.C. this is for you.)


WHY IS THIS DEVICE IMPORTANT?


The medical impact of this device could weigh in for cancer patients who may need to use autologous (one's own) stem cells for their treatment. These cancer patients are treated with chemotherapy to reduce and eliminate as many of the malignant circulating cancer cells as possible from the bloodstream and bone marrow. The treating doctor will collect the patient's own stem cells during this period of remission when the cancer load is at its lowest.

The patient's own stem cells are stimulated using GCSF (read about it here) and the stem cells are harvested and stored in anticipation of the possibility that the cancer cells will multiply again, requiring another round of chemotherapy which may damage the existing healthy marrow further. The collected stem cells will be infused back to the patient to ensure that the patient has sufficient stem cells to repopulate and replenish the marrow, thereby restoring normal cell levels to the bloodstream.

To address the concern that perhaps cancer cells from the patient might also be collected in the same fraction as the healthy stem cells (impossible to distinguish during harvesting) this device could lend a hand to filter out the cancer cells inside or out of the patient's body, i.e. the cancer cells would travel around the bloodstream until they reach the shunt, where they would then be immobilized.

Note though, that the inventors have conceded that this device will not be able to collect enough stem cells for a transplant, therefore the customary stem cell collection procedures will still need to be performed.


SOME INTERESTING STATISTICS


According the A/Prof. King, the shunt placed in an non-GCSF induced rat in a 2 hour period enabled the capture of 3-4 times the number of usual stem cells obtained in normal circulating bloodstream (approx 1%). Hence the device is thought to attract and specifically retain a significantly higher number of stem cells.

This stem cell number could be significantly higher in patients who have been mobilized.


WHAT ELSE CAN IT DO?


Well, it is a concept device which will be as good as its selectin coating. A/Prof. King has already forecasted the use of the device in trapping specific cancer cells in the body to prevent metastatic spread and layering in proteins which could help steer cell development processes by differentiating them while passing through the shunt. (analogy: think sticky mats for dust, sticky mats for cockroaches, sticky mats for cat fur...all requiring different levels of stickiness for its target)



WHEN CAN I BUY IT?


The entrepreneurial A/Prof. King has already started a company by the name of CellTraffix and the anti-metastasis implants are set for animal trials later this year in collaboration with bioengineers Professor Jeffrey Karp and Robert Langer at Harvard and MIT who will develop stable selectin coatings that will last over months than days. Meanwhile, the CEO of CellTraffix, Tom Fitzgerald has already announced that the company's first product for researchers to capture stem cells or cancer cells for lab experimentation will be marketed by early 2009, with clinical testing of the anti-cancer coatings in 2010.


Read how a chance encounter between a bioengineer and a haematology clinician gave rise to this work and watch the cells being captured here (note that you will need a high speed broadband connection as the video files are rather large).


*Why does this remind me of the movie Inner Space I hear you ask... well the term cell capturing device often conjurs up the image of a little machine (like the exploration submersible the protaganist uses) to grab and hold onto cells in circulation :)

Brain Stem Cells killed by Space Radiation

A lot of the concepts surrounding that of anti-aging first involves protecting and conserving what the body has left to the best of your ability and secondly attempting to regenerate and increase the number of functionally productive living cells in the desired tissues and organs.

In a previous blog entry, I described a face cream by Dior (Capture) which promises to protect and nourish the remaining stem cells one has left in wrinkled skin. If you are a frequent long-haul air traveller (Richard Quest please take note), you might wish to give a small thought to this rather esoteric but possibly significant research study -which was conducted by the researchers at Cold Spring Harbor, Brookhaven National Laboratory, the Kennedy Space Center and the University of Florida- published the the Journal of Experimental Neurology.

For those of us who spend enough time in the airplane and feel that we could have reached Mars and back, we might wish to consider plausible types of protection for the stem cells in our brain responsible for learning and memory.

In the preparative research for the proposed next NASA project to put a man on Mars, scientists conducted an experiment with mice where a single dose of radiation was administered considered to be equivalent to the amount an astronaut might be exposed to during a 3 year space voyage to Mars and back. What they found was that the radiation particularly affected the stem cells in the region of the hippocampus.


"We are going to have to rethink our understanding of stem cell susceptibility to radiation, including cosmic radiation encountered during space travel, as well as radiation doses that accompany different medical procedures," said Professor Dennis Steindler of the University of Florida, co-investigator of the study.


WHAT IS COSMIC RADIATION AND IS IT SOMETHING TO WORRY ABOUT?

Well, this really depends on how much long haul, high altitude flying you get to do as part of your job. Air crew and presumably flight military will be subjected to the highest amounts of exposure. Background cosmic radiation at ground level have been established at 2-3 mSv (microSievert) which is considered natural exposure. In the plane, higher altitudes reduces the protective layers in the atmosphere which shield most of the cosmic radiation and thus cosmic radiation exposure is increased. If you'd like to have an indication of cosmic radiation levels during flight, have a look at this table on the WHO site. (Note: if you're flying the A380 long distance at 43,000 feet, you'll need to double the figures up by 2)

As a result of this, aircrew are now monitored and their time tables adjusted accordingly to ensure that they do not exceed the recommended dose. The WHO and the UK Department for Transport also does not recommend pregnant air stewardesses to work on flights due to the exposure to the unborn child.

Or we can live near the equator where cosmic radiation is reduced by half.



HOW CAN WE PROTECT OUR STEM CELLS FROM COSMIC RADIATION?

Come to think of it, maybe those Imperial Stormtroopers might have been wearing reasonable looking outfits for the fight and flights through space to protect their cells. Ridiculous as it may have been (note that Luke and Leia never wore any type of helmet or protective outfit) astronauts going out on a space walk have to put up with much more cumbersome outfits due to the numerous protective layers.

A CHALLENGE FOR SPACE BIOENGINEERS AND PHYSICISTS

NASA engineering scientists are working on new materials and polymers which confer more protection and estimate that a new spacesuit which will be worn by the super-fit astronauts on Mars will be as light as 21 Kg and comprise of 12 different layers.

Better shielding on spacecrafts are also on the way (using water as an absorbent material) and hopefully, some of this technology will also filter down for use in commercial flights so that we can reduce our cancer risk (bad enough already) and retain as many hippocampal stem cells as possible.

As for the rest of us who are already losing our memory and learning capabilities due to cosmic radiation, we'll have to see about how to potentially replace and regenerate new stem cells along the way without resorting to NASA designed storm trooper outfits when we board the A380 from Singapore to London or New York.