Professor Josef Käs and Dr Jochen Guck from the University of Leipzig have developed a procedure that can extract and isolate embryo-quality stem cells from adult blood for the first time. This new technique could unlock the stem cell revolution and stimulate a boom in medical research using stem cells.
Stem cells are cells which have not yet differentiated into specialised tissues such as skin, brain or muscle. They promise a new class of regenerative medicine, which could repair apparently permanent damage such as heart disease or Parkinson's. The cells are currently taken from aborted human foetuses, an issue which has led to controversy and opposition in many parts of the world. Any alternative source, such as voluntary adult donations, could spark a boom in new cures.
Scientists have known for some time that stem cells exist in adult human blood and certain other tissues. However the only reliable way to separate them involved marking the cells with a chemical dye, rendering them useless for medical purposes. Professor Käs' technique for the first time uses a physical characteristic of each cell – its stretchiness or elasticity – instead of its biological make-up, to decide whether or not it's a stem cell. Stem cells don't need a rigid "cytoskeleton" to hold them in shape, which makes them stretchier than normal cells.
Käs and Guck's machine uses a powerful beam of infrared laser light to stretch and measure cells one by one. His optical stretcher differs from an existing tool known as optical tweezers in which the light is focused to a sharp point to grab hold of a cell. In contrast, the optical stretcher uses un-focused light. This allows laser beams strong enough to detect stretching to be used without killing the cell.
According to Dr Michael Watts, an expert in haematology and stem cells at University College London, there are just 10,000 primitive cells in the average adult's bloodstream. Of those, only 500 might have the potential to replace embryonic stem cells. Stem cell research requires millions of these cells.
Bone marrow donors are routinely treated with a drug known as G-CSF which "mobilises" stem cells from the bone marrow into the blood. After G-CSF treatment the donor's blood is passed through a centrifuge and back into their body, akin to a kidney dialysis machine, harvesting two or three hundred million primitive cells in the process.
Various properties of these primitive cells have been used to try and isolate the 5% or so with the highest stem cell potential, but no single technology has proved completely successful for human stem cells. This is where the optical stretcher could come to the rescue, picking those cells one by one according to the strength of their cytoskeletons. Watts explains that such an advance could have far-reaching consequences for medical treatments. "We could add significantly to our knowledge of stem cell biology toward developing cellular therapies," he says.
The optical stretcher can already test 3,600 cells per minute. This is not yet fast enough for industrial separation of millions of high grade stem cells, but it promises a realistic alternative to embryo use if it can be scaled up. Meanwhile, it is already being used to isolate low-grade stem cells which can develop into skin. In collaboration with medical professionals in Leipzig, elderly patients are being treated for persistent non-healing wounds. Low-grade stem cells isolated from the patient's own blood are applied to the wound to kick-start the healing process.
Professor Josef Käs is Director of the Institute for Soft Matter Physics at the University of Leipzig, Germany.
Contact: Professor Josef Käs, Institute for Soft Matter Physics, University of Leipzig, Email: jkaes@physik.uni-leipzig.de, Tel: 49-341-973-2471 , Secretary: Claudia Honisch, tel. 49-341-973-2470 Mobile: 0179-904-3672, Home: 49-341-124-8944
Josef Käs research webpage: http://www.softmatterphysics.com/
Professor Käs is available for interviews: Contact David Reid, Institute of Physics, 44-207-470-4815 to arrange an interview.
Notes to editors:
Delivery: This presentation will be delivered at 11:30am Tuesday 12th April 2005.
Physics 2005 takes place at the University of Warwick from 10th – 14th April 2005. It is the main academic conference for the UK physics community during Einstein Year and the largest gathering of physicists in the UK. At the meeting scientists will present exciting new research from emerging fields in physics.
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Einstein Year is a year-long celebration of physics and its relevance to all our lives. Marking the centenary of Einstein's three ground-breaking ideas it communicates the vital role physics plays in developing new technologies such as cancer screening equipment and mobile phones, whilst addressing big questions like how the Universe was created and how climate change can be addressed. Einstein Year will inspire and inform the next generation of physicists as well as those who are just curious about the world around them. Einstein Year is the UK and Ireland's contribution to International Year of Physics, a UN-sponsored project to promote physics in 2005.
Einstein Year is a year-long celebration of physics and its relevance to all our lives. Marking the centenary of Einstein's three ground-breaking ideas it communicates the vital role physics plays in developing new technologies such as cancer screening equipment and mobile phones, whilst addressing big questions like how the Universe was created and how climate change can be addressed. Einstein Year will inspire and inform the next generation of physicists as well as those who are just curious about the world around them. Einstein Year is the UK and Ireland's contribution to International Year of Physics, a UN-sponsored project to promote physics in 2005.
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