The project for the first head transplant in man is code-named HEAVEN/GEMINI (Head Anastomosis Venture with Cord Fusion.
The technical hurdles have now been cleared thanks to cell engineering. As described in his paper, the keystone to successful spinal cord linkage is the possibility to fuse the severed axons in the cord by exploiting the power of membrane fusogens/sealants. Agents exist that can reconstitute the membranes of a cut axon and animal data have accrued since 1999 that restoration of axonal function is possible. One such molecule is poly-ethylene glycol (PEG), a widely used molecule with many applications from industrial manufacturing to medicine, including as an excipient in many pharmaceutical products. Another is chitosan, a polysaccharide used in medicine and other fields.
HEAVEN capitalizes on a minimally traumatic cut of the spinal cord using an ultra-sharp blade (very different from what occurs in the setting of clinical spinal cord injury, where gross, extensive damage and scarring is observed) followed within minutes by chemofusion (GEMINI). The surgery is performed under conditions of deep hypothermia for maximal protection of the neural tissue. Moreover, and equally important, the motoneuronal pools contained in the cord grey matter remain largely untouched and can be engaged by spinal cord stimulation, a technique that has recently shown itself capable of restoring at least some motor control in spinal injured subjects.
Surgical Neurological International - HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI)
* a head of a monkey was transplanted in the 1970s but the spinal cord could not be repaired at the time
* Spinal cords have been regrown in rats.
Over the last 30 years, scientists have worked to chemically encourage regrowth. Two chemicals, chondroitinase and FGF, show strong signs of doing exactly that--in rats, at least. Independently, over the past three decades, each chemical has shown some promise in restoring simple but crucial rat motor processes, like breathing, even with entirely severed spinal cords.
Two surgeons in the field figured that a combination of the chemicals might enhance the regrowth even more. The surgeons, from Case Western Reserve University and the Cleveland Clinic, began by entirely severing the spinal cords of 15 rats to ensure no independent, natural regrowth. That shut off the rats' bladder control (a nervous system process that is especially important in rats, since they urinate often and to mark their territory). The researchers then injected the two growth-stimulating chemicals into both sides of the severance, and reinforced the gap in the cord with steel wiring and surgical thread.
The Cleveland clinic has the full description of the rat spinal cord repair.
Read more »
Reposted via Next Big Future
The technical hurdles have now been cleared thanks to cell engineering. As described in his paper, the keystone to successful spinal cord linkage is the possibility to fuse the severed axons in the cord by exploiting the power of membrane fusogens/sealants. Agents exist that can reconstitute the membranes of a cut axon and animal data have accrued since 1999 that restoration of axonal function is possible. One such molecule is poly-ethylene glycol (PEG), a widely used molecule with many applications from industrial manufacturing to medicine, including as an excipient in many pharmaceutical products. Another is chitosan, a polysaccharide used in medicine and other fields.
HEAVEN capitalizes on a minimally traumatic cut of the spinal cord using an ultra-sharp blade (very different from what occurs in the setting of clinical spinal cord injury, where gross, extensive damage and scarring is observed) followed within minutes by chemofusion (GEMINI). The surgery is performed under conditions of deep hypothermia for maximal protection of the neural tissue. Moreover, and equally important, the motoneuronal pools contained in the cord grey matter remain largely untouched and can be engaged by spinal cord stimulation, a technique that has recently shown itself capable of restoring at least some motor control in spinal injured subjects.
Surgical Neurological International - HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI)
* a head of a monkey was transplanted in the 1970s but the spinal cord could not be repaired at the time
* Spinal cords have been regrown in rats.
Over the last 30 years, scientists have worked to chemically encourage regrowth. Two chemicals, chondroitinase and FGF, show strong signs of doing exactly that--in rats, at least. Independently, over the past three decades, each chemical has shown some promise in restoring simple but crucial rat motor processes, like breathing, even with entirely severed spinal cords.
Two surgeons in the field figured that a combination of the chemicals might enhance the regrowth even more. The surgeons, from Case Western Reserve University and the Cleveland Clinic, began by entirely severing the spinal cords of 15 rats to ensure no independent, natural regrowth. That shut off the rats' bladder control (a nervous system process that is especially important in rats, since they urinate often and to mark their territory). The researchers then injected the two growth-stimulating chemicals into both sides of the severance, and reinforced the gap in the cord with steel wiring and surgical thread.
The Cleveland clinic has the full description of the rat spinal cord repair.
Read more »
Reposted via Next Big Future
No comments:
Post a Comment