The issue of immunology in stem cell therapies: a pharmaceutical ...
Stem-cell therapies here to stay–but from where?
1
For personal use. Only reproduce with permission from The Lancet Publishing Group. that the field is too new to know which cell source ultimately will be most appropriate. “Our work shows that we can mimic normal development of the midbrain in tissue culture”, notes McKay. “Perhaps the adult cells can reach the same endpoint. We don’t know yet.” For Sanberg, the debate needs to include embryonic and post-birth tissues, such as umbilical-cord blood. “I have no doubt that we will continue to be able to translate findings and techniques discovered in embryonic cells to post-birth and adult cells, and vice versa”, he says, pointing to recent reports in a special neuroscience issue of Cell Transplantation (2002; 4: issue 3). “That is why research in both areas needs to continue.” Kelly Morris THE LANCET Neurology Vol 1 August 2002 http://neurology.thelancet.com 204 Never before have prospects for stem- cell therapies looked so good, particularly to replace or regenerate neural tissue. But despite the recent surge in scientific reports (Lancet Neurology 2002; 1: 144), experts are keeping an open mind on the source of stem cells for clinical purposes. Current research focuses on stem cells from embryonic tissue (ES cells) or adult tissue, including bone marrow and brain. Recent research is expected to rekindle the debate on the relative merits of adult stem cells versus ES cells. Catherine Verfaillie and colleagues (University of Minnesota, Minneapolis, MN, USA) report the presence of rare cells in adult mouse bone marrow that seem to respond to organ-specific cues, just like ES cells. These multipotent adult progenitor cells “proliferate extensively without obvious senescence or loss of differentiation potential”, say the authors, so “they may be an ideal cell source for therapy of inherited or degenerative disease” (Nature 2002; 418: 41–49). Meanwhile, a group led by Ron McKay (National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA) show that dopaminergic neurons generated from cultured ES cells can fully restore electrophysiological and motor function in Parkinson’s disease, at least in a rat model. The group says these findings “encourage the use of ES cells in cell- replacement therapy for Parkinson’s disease” (Nature 2002; 418: 50–56), and, says McKay, are also important in a wider context: “They imply that stem- cell manipulation in vitro will become a tool used in many fields of medicine.” According to Paul Sanberg (University of South Florida, Tampa, FL, USA), another encouraging aspect of these findings is that “they continue to support the view that once a neural stem or progenitor cell is differentiated, they do not form tumours or teratomas following transplantation”. He believes such evidence “will be supportive in bringing these therapies to the clinic”. McKay responds pragmatically to the issue of embryonic versus adult stem cells: “We need cells that work whatever their source.” Expert opinion suggests Stem-cell therapies here to stay—but from where? Technology for telekinesis Newsdesk Catherine Verfaillie Courtesy of Nature Publishing Group Monkeys can be trained to move a cursor on a computer screen by thought alone, according to US researchers. This technology may enable patients with paralysed or amputated limbs to control robotic prostheses neurally. Dawn Taylor and co-workers (Arizona State University, Tempe, AZ, USA) implanted electrodes into the cerebral cortex of macaque monkeys to measure activity of neurons that control arm movements. First, the monkeys guided a cursor towards targets on a computer screen with their arm movements and the researchers recorded the neural activity. Next, the monkeys’ arms were restrained and first set of measure- ments used to convert neural activity directly into on-screen movement of the cursor. The monkeys tried to move their arms at first but eventually realised they could move the cursor by thought alone. Calibration of actual movement with neural activity would not be possible in patients who do not have the use of their limbs. However, the authors report that they have “developed a ‘coadaptive’ movement prediction algorithm that does not require physical limb movements or any a priori knowledge of cell tuning properties”, which could be used in patients with paralysed or amputated limbs (Science 2002; 296: 1829–32). The most encouraging finding is that the monkeys processed visual feedback quickly enough to change the direction of cursor movement during each task; they also improved between tasks. This is the first time that individual neurons have been shown to adapt and improve performance during task. This improvement suggests that controlling the cursor is a new skill that must be learnt. “Further studies are needed to explore the long-term development and maintenance of this new skill”, says John Wolpaw (New York State Department of Health, NY, USA), “which depends on continued effective interaction between two adaptive controllers—the user’s brain and the system that is processing the brain signals.” Taylor’s team plans to investigate whether monkeys can control a robot arm in this way. This technology could lead to brain-controlled prostheses. Eventually, stimulation of patients’ muscles may help restore function to their own limbs. However, as Wolpaw warns, “the clinical practicality and the applicability of systems based on invasively recorded brain signals remain to be explored”. Peter Hayward Rights were not granted to include this image in electronic media. Please refer to the printed journal.
-
Upload
kelly-morris -
Category
Documents
-
view
215 -
download
1
Transcript of Stem-cell therapies here to stay–but from where?
For personal use. Only reproduce with permission from The Lancet Publishing Group.
that the field is too new to know whichcell source ultimately will be mostappropriate. “Our work shows that wecan mimic normal development of the
midbrain in tissue culture”, notesMcKay. “Perhaps the adult cells canreach the same endpoint. We don’tknow yet.”
For Sanberg, the debate needs toinclude embryonic and post-birthtissues, such as umbilical-cord blood. “Ihave no doubt that we will continue tobe able to translate findings andtechniques discovered in embryoniccells to post-birth and adult cells, andvice versa”, he says, pointing to recentreports in a special neuroscience issue ofCell Transplantation (2002; 4: issue 3).“That is why research in both areasneeds to continue.”Kelly Morris
THE LANCET Neurology Vol 1 August 2002 http://neurology.thelancet.com204
Never before have prospects for stem-cell therapies looked so good,particularly to replace or regenerateneural tissue. But despite the recentsurge in scientific reports (LancetNeurology 2002; 1: 144), experts arekeeping an open mind on the source ofstem cells for clinical purposes.
Current research focuses on stemcells from embryonic tissue (ES cells) oradult tissue, including bone marrowand brain. Recent research is expectedto rekindle the debate on the relativemerits of adult stem cells versus ES cells.
Catherine Verfaillie and colleagues(University of Minnesota, Minneapolis,MN, USA) report the presence of rarecells in adult mouse bone marrow thatseem to respond to organ-specific cues,just like ES cells. These multipotentadult progenitor cells “proliferateextensively without obvious senescenceor loss of differentiation potential”, saythe authors, so “they may be an ideal cellsource for therapy of inherited ordegenerative disease” (Nature 2002; 418:41–49).
Meanwhile, a group led by RonMcKay (National Institute ofNeurological Disorders and Stroke,Bethesda, MD, USA) show thatdopaminergic neurons generated fromcultured ES cells can fully restoreelectrophysiological and motor functionin Parkinson’s disease, at least in a ratmodel. The group says these findings“encourage the use of ES cells in cell-replacement therapy for Parkinson’sdisease” (Nature 2002; 418: 50–56), and,says McKay, are also important in awider context: “They imply that stem-cell manipulation in vitro will become atool used in many fields of medicine.”
According to Paul Sanberg(University of South Florida, Tampa,FL, USA), another encouraging aspectof these findings is that “they continueto support the view that once a neuralstem or progenitor cell is differentiated,they do not form tumours or teratomasfollowing transplantation”. He believessuch evidence “will be supportive inbringing these therapies to the clinic”.
McKay responds pragmatically tothe issue of embryonic versus adult stemcells: “We need cells that work whatevertheir source.” Expert opinion suggests
Stem-cell therapies here to stay—but from where?
Technology for telekinesis
Newsdesk
Catherine Verfaillie
Cou
rtes
y of
Nat
ure
Publ
ishi
ng G
roup
Monkeys can be trained to move acursor on a computer screen bythought alone, according to USresearchers. This technology mayenable patients with paralysed oramputated limbs to control roboticprostheses neurally.
Dawn Taylor and co-workers(Arizona State University, Tempe, AZ,USA) implanted electrodes into thecerebral cortex of macaque monkeysto measure activity of neurons thatcontrol arm movements. First, themonkeys guided a cursor towardstargets on a computer screen withtheir arm movements and theresearchers recorded the neuralactivity. Next, the monkeys’ arms wererestrained and first set of measure-ments used to convert neural activitydirectly into on-screen movement ofthe cursor. The monkeys tried to movetheir arms at first but eventuallyrealised they could move the cursor bythought alone.
Calibration of actual movementwith neural activity would not bepossible in patients who do not havethe use of their limbs. However, theauthors report that they have“developed a ‘coadaptive’ movementprediction algorithm that does notrequire physical limb movements orany a priori knowledge of cell tuningproperties”, which could be used in
patients with paralysed or amputatedlimbs (Science 2002; 296: 1829–32).
The most encouraging finding isthat the monkeys processed visualfeedback quickly enough to change thedirection of cursor movement duringeach task; they also improved betweentasks. This is the first time thatindividual neurons have been shownto adapt and improve performanceduring task.
This improvement suggests thatcontrolling the cursor is a new skillthat must be learnt. “Further studiesare needed to explore the long-termdevelopment and maintenance of thisnew skill”, says John Wolpaw (NewYork State Department of Health, NY,USA), “which depends on continuedeffective interaction between twoadaptive controllers—the user’s brainand the system that is processing thebrain signals.”
Taylor’s team plans to investigatewhether monkeys can control a robotarm in this way. This technology couldlead to brain-controlled prostheses.Eventually, stimulation of patients’muscles may help restore function totheir own limbs. However, as Wolpawwarns, “the clinical practicality and theapplicability of systems based oninvasively recorded brain signalsremain to be explored”.Peter Hayward
Rights were notgranted to include this
image in electronicmedia. Please refer to
the printed journal.
