Stem Cell Research

Neural Stem Cells Regenerate Relay Circuits; New Axons Formed Across Severe Spinal Cord Injury

Interesting in light of the spinal cord neural stem cell human trials being planned by Neuralstem (CUR) and currently underway by StemCells Inc. (STEM). 

In the new University research, scientists were able to regenerate “an astonishing degree” of axonal growth at the site of severe spinal cord injury in rats.  Their research revealed that early stage neurons have the ability to survive and extend axons to form new, functional neuronal relays across an injury site in the adult central nervous system (CNS).

The study also proved that at least some types of adult CNS axons can overcome a normally inhibitory growth environment to grow over long distances.  Importantly, stem cells across species exhibit these properties.

Researchers embedded neural stem cells in a matrix of fibrin -- a protein key to blood clotting already used in human neuron procedures -- mixed with growth factors to form a gel.  The gel was then applied to the injury site in rats with completely severed spinal cords.

Positive Interim Data From Spinal Cord Injury Trial Reported By StemCells, Inc.

StemCells Inc. reported that interim six-month data from the first patient cohort in a Phase I/II clinical trial of its HuCNS-SC product candidate -- purified human neural stem cells -- for chronic spinal cord injury demonstrates a favorable safety profile and shows gains in sensory function in two of the three patients compared to pre-transplant baselines. The third patient remains stable. The trial is being conducted in Zurich, Switzerland at the University Hospital Balgrist, University of Zurich. The trial is scheduled to end at 12 months.

In general stem cell therapeutic candidates have shown good saftey profiles in the phase one clinical trials both within and outside the United States. As phase II trials begin we will learn more about efficacy in various indications and much more will be known about the potential for actual therapies. Some Sector Companies are already hesitating at the door to Phase II awaiting investor or partner money to procede. In this context StemCells Inc. had net cash resources at June 30 of approximately $5 million. While The California Institute for Regenerative Medicine (CIRM) approved an award to StemCells Inc. for up to $20 million under CIRM's Disease Team Therapy Development Award program (RFA 10-05), the award is to fund preclinical development of StemCells' purified human neural stem cells product candidate as a potential treatment for cervical spinal cord injury.

Patients in the study's first cohort all suffered a complete injury to the thoracic (chest-level) spinal cord. In a complete injury, there is no neurological function below the level of injury. All three patients were transplanted four

Successful Integration Of Embryonic Stem Cells Into Spinal Cord Reduces Neuropathic Pain

The findings suggest avenues for clinical strategies aimed at correcting the underlying disease pathology as opposed to treating the symptoms of chronic debilitating pain.

"Pharmacological approaches to managing neuropathic pain enhance GABA-mediated inhibition. However, some patients do not respond to these therapies and there are significant adverse side effects," said Dr. Allan Basbaum from the University of California, San Francisco.

There are two major classes of chronic pain: inflammatory pain that results from injury to tissue, such as muscle and bone, and neuropathic pain from injury to nerves, for example, in the limbs or face. Damage to nerves can occur after physical trauma and from chemotherapy drugs. With neuropathic pain, the pain occurs in the absence of stimulation, and there is hypersensitivity and exacerbated pain to stimuli that would not normally cause pain.

UCSD Research Sheds Possible Light On Geron Spinal Stem Cell Treatment Prospects

Geron Corp.'s Investigational New Drug (IND) application for the clinical trial of GRNOPC1 in patients with acute spinal cord injury was placed on hold by the FDA while new animal study data supplied by the company is evaluated (Geron's explanation of the submitted data is at the bottom of this post).

Prior to the hold, Geron was in the process of initiating a Phase I multi-center trial that is designed to establish the safety of GRNOPC1 in patients with "complete" American Spinal Injury Association (ASIA) grade A subacute thoracic spinal cord injuries.

While the FDA approval of Gerron's IND was to establish the safety of embryonic stem cells in a therapeutic setting, Gerron's goal was not only to establish safety but "the restoration of organ and tissue function achieved by the injection of healthy replacement cells," according to Thomas Okarma, Ph.D., M.D., Geron's president and CEO. "The ultimate goal for the use of GRNOPC1," he added, "is to achieve restoration of spinal cord function by the injection of hESC-derived oligodendrocyte progenitor cells directly into the lesion site of the patient's injured spinal cord."

Now, also moving one step closer to developing a possible therapy for repairing spinal cord injuries, scientists at the University of California San Diego say they have successfully guided regenerating nerve axons to cell targets, where they re-establish connections essential to any recovery.

“With this advance, we've shown it's possible to direct an axon to find the correct target from among potentially millions of incorrect ones in the spine and brain and make the right connection,” said Dr. Mark Tuszynski, a professor of neurosciences and part of a research team from UCSD, the San Diego Veterans Affairs Medical Center and UCLA.

Geron Recieves FDA Approval To Begin World's First Human Clinical Trial of An Embryonic Stem Cell-Based Therapy

This is Monday after the Friday morning announcement of the first Phase I trial of an embryonic stem cell therapy.  At this writing Geron's market cap ($645M) is now greater than that of Osiris Therapeutics ($619M).  Osiris is in Phase III trials with Prochymal (not for spinal cord repair), a mesenchymal stem cell therapeutic application derived from adult bone marrow stem cells.  Everything points to Osiris obtaining approval to market Prochymal by the end of 2010.  Prochymal will in all probability be the first stem cell therapeutic application approved for market distribution.

Geron's market cap totaled $415 million at close of market on Thursday.  This morning it hit $650 million before ending the day around $645M.  This $230 million or so increase in market cap is the direct result of the FDA acceptance of the idea (based on the largest investigational drug application - 22,000 pages - ever submitted) that embryonic stem cells are safe enough to test in a small number of human beings (8 to 10 people is the test size).

Regenerative Medicine And Stem Cells, A Summary

Cell sources used to rebuild damaged tissues are the major issue in the development of regenerative medicine.  Three sources of cells can be tapped for transplant: differentiated tissues (refers to a technique developed at Harvard and posted here in August 2008, a better approach to the production of Induced Pluripotent Stem Cells), adult stem cells (ASCs) and derivatives of embryonic stem cells (ESCs). Adult stem cells regenerate epithelia, brain tissue, muscle, blood and bone. They have also been found in other tissues that normally scar after injury, such as myocardium, spinal cord and retinal tissues.

Stem Cells And Spinal Cord Injuries

Researchers have found that manipulating stem cells prior to transplantation may hold the key to overcoming a critical obstacle to using stem cell technology to repair spinal cord injuries.

This particular research focused on a major support cell in the central nervous system called an astrocyte. When nerve fibers are injured in the spinal cord, the severed ends of the nerve fibers fail to regenerate and reconnect with the nervous system circuitry beyond the site of the injury. During early development, astrocytes are highly supportive of nerve fiber growth, and scientists believe that if properly directed, these cells could play a key role in regenerating damaged nerves in the spinal cord.

UC Irvine Results Confirm MIT Brain Stem Cell Location Study

Evidence indicates that the true stem cells in the mammalian brain are the ependymal cells that line the ventricles in the brain and spinal cord, rather than cells in the subventricular zone as biologists previously believed. Brain ventricles are hollow chambers filled with fluid that supports brain tissue, and a layer of ependymal cells lines these ventricles. This finding at UC Irvine supports the finding of MIT researchers posted here a few days ago.

UC Irvine scientists have shown that with proper stimulation they can produce new brain cells to replace those lost to disease or injury.  Ependymal cells line the fluid-filled ventricles, so a drug to activate the cells could theoretically travel through this fluid directly to the stem cells.

Step Taken Toward Spinal Cord Stem Cell Paralysis Solution

Researchers have pinpointed stem cells within the spinal cord that, if persuaded to differentiate into more healing cells and fewer scarring cells following an injury, may lead to a new, non-surgical treatment for debilitating spinal-cord injuries.

Injuries of the spinal cord resulting from trauma that fractures or dislocates vertebrae are usually characterized by broken pieces of vertebrae tearing into cord tissue or pressing on nerves.  In the worst case, the cord can no longer relay messages below the point of injury and the victim is paralyzed.

The tiny number of stem cells in the adult spinal cord proliferate slowly or rarely, and fail to promote regeneration on their own. But recent experiments show that these same cells, grown in the lab and returned to the injury site, can restore some function in paralyzed rodents and primates.

Spinal Cord: Geron Corp Prepares For First Stem Cell Clinical Trials

  Over a quarter of a million people in the U.S. suffer from spinal injuries, with around 11,000 new cases added each year.  Geron Corp., speaking with confidence on the possibility of human application, intends to move its pre-clinically heavily-tested embryonic stem cell application for spinal cord injuries into the clinical phase of testing. This will mark the first time this has been done and will be a notable benchmark in stem cell research.

Spinal Cord Injury: Progress Reported Using Cord Blood Stem Cells Treated With Lithium Salt

    StemCyte, a cord blood banking company with a proprietary line of products, has expanded its support of spinal cord injury researcher, Dr. Wise Young, through an agreement with Rutgers University. Wise Young, M.D., Ph.D., founding director of the W.M. Keck Center for Collaborative Neuroscience at Rutgers University, has concluded in a preclinical (other than human subjects) study that, treated with lithium salt, Cord Blood Stem Cells are the only type of stem cell with neurotrophic (capable of signaling particular cells to survive, differentiate, or grow) effect in the potential treatment of spinal cord injuries.  "UCB (umbilical cord blood) stem cells have a greater production or expression of growth factors such as cell survival factors, anti-differentiation factors and combinations than other types of stem cells when  treated with lithium salt," said Dr. Young. "As a result, we believe these cells will have significant therapeutic benefit and hope to treat our first patient in clinical trials later this year."

    StemCyte Inc., a privately owned cord blood banking company, has entered into a Research and Licensing Agreement with Rugers University specifically to advance this research.  StemCyte will provide financial sponsorship for Dr. Young's work at Rutgers' W. M. Keck Center for Collaborative Neuroscience and will receive exclusive commercialization rights to this therapy.  If successfull, Rutgers will be paid a licensing fee.