Nose Stem Cells Help Bulgarian Man Walk With Braces


Darek Fidyka, a 38-year-old Bulgarian man, was severely injured by a stab wound in 2010 and consequently lost the ability to walk.

Now, a new procedure using stem cells from his nose has given him the ability to walk with the help of braces.

Olfactory ensheathing cells or OECs (also known as olfactory ensheathing glial or OEGs) are found in the olfactory system, inside the skull and in the covering of cells that lines the roof of the nose. OECs share similarities to other glial cells like Schwann cells, astrocytes, and oligodendrocytes. OECs can aid the extension of neural projections known as axons from the nasal tissue to the olfactory glomeruli. OECs can do this because they secrete several interesting neurotrophic factors and cell adhesion molecules and migrate along with the regenerating axons. Because of these properties, OECs can escort axonal extension through glial scars that are made in a spinal cord after a spinal cord injury. These scars inhibit the outgrowth of new axons but OECs can allow regenerating axons to bridge these glial scars.

An advantage of OECs is that they can coexist with astrocytes, the cells that contribute to the formation of the glial scar, and even seem to prevent the out-of-hand response astrocytes have in response to injury in which they synthesize a host of molecules that inhibit axon regeneration called “inhibitory proteoglycans.”

The pioneering technique used in this procedure, according to Geoffrey Raisman, a professor at University College London’s (UCL) institute of neurology, used OECs to construct a kind of bridge between two stumps of the damaged spinal column.

“We believe… this procedure is the breakthrough which, as it is further developed, will result in a historic change in the currently hopeless outlook for people disabled by spinal cord injury,” said Riesman, who led this research project.

Raisman, who is a spinal injury specialist at UCL, collaborated with neurosurgeons at Wroclaw University Hospital in Poland to remove one of Fidyka’s olfactory bulbs, which give people their sense of smell, and transplant his olfactory ensheathing cells (OECs) in combination with. olfactory nerve fibroblasts (ONFs) into the damaged spinal cord areas. Following 19 months of treatment, Fidyka recovered some voluntary movement and some sensation in his legs.

The Nicholls Spinal Injury Foundation, a British-based charity which part-funded the research, said in statement that Fidyka was continuing to improve more than predicted, and was now able to drive and live more independently.

OECs have been used before to treat spinal cord injury patients. I refer you to chapter 27 in my book, The Stem Cell Epistles, to learn more about these. The novel technique in this paper is the additional use of nasal fibroblasts and the construction of a bridge between the two damaged remnants of the spinal cord.

The reason OECs were recruited to treat spinal cord injuries is that when axons that carry information about smells are damaged, the neuron simply regenerates its atonal extension, which grows into the olfactory bulbs. OECs facilitate this process by re-opening the surface of the olfactory bulbs in order for the new axons to enter them. Thus Raisman and others have the notion that transplanted OECs in the damaged spinal cord could equally facilitate the regeneration of severed nerve fibers.

Raisman also added that the technique used in this case, that is bridging the spinal cord with nerve grafts from the patient, had been used in animal studies for years, but was never used in a human patient in combination with OECs.

“The OECs and the ONFs appeared to work together, but the mechanism between their interaction is still unclear,” he said in a statement about the work.

Several spinal cord injury experts who were not directly involved in this work said its results offered some new hope. However, they were also quick to add that more work needed to be done to precisely determine what had led to this success. More patients must be successfully treated with this procedure before its potential can be properly assessed.

“While this study is only in one patient, it provides hope of a possible treatment for restoration of some function in individuals with complete spinal cord injury,” said John Sladek, a professor of neurology and pediatrics at the University of Colorado School of Medicine in the United States.

Raisman and his team now plan to repeat the treatment technique in between three and five spinal cord injury patients over the next three to five years. “This Nose will enable a gradual optimization of the procedures,” he told Reuters.

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Gene Inhibitor Plus Fish Fibrin Restore Nerve Function Lost After a Spinal Cord Injury


Scientists at UC Irvine’s Reeve-Irvine Research Center have discovered that injections of salmon fibrin injections into the injured spinal cord plus injections of a gene inhibitor into the brain restored voluntary motor function impaired by spinal cord injury.

Gail Lewandowski and Oswald Steward, director of the Reeve-Irvine Research Center at UCI, examined rodents that had received spinal cord injuries.  They were able to heal the damage by developmentally turning back the clock in a molecular pathway that is critical to the formation of the corticospinal nerve tract, and by providing a scaffold for the growing neurons so that the axons of these growing neurons could grow and make the necessary connections with other cells.  Their research was published in the July 23 issue of The Journal of Neuroscience.

The work of Steward and Lewandowski is an extension of previous research at UC Irvine from 2010.  Steward and his colleagues discovered that the axon of neurons grow quite well once an enzyme called PTEN is removed from the cells.  PTEN is short for “phosphatase and tensin homolog,” and it removes phosphate groups from specific proteins and lipids.  In doing so, PTEN signals to cells to stop dividing and it can also direct cells to undergo programmed cell death (a kind of self-destruct program).  PTEN also prevents damaged tissues from regenerating sometimes, because it is a protein that puts the brakes of cell division.  Mutations in PTEN are common in certain cancers, but the down-regulation of PTEN is required for severed axons to re-form, extend, migrate to their original site, and form new connections with their target cells.

PTEN function

 

After two years, team from U.C. Irvine discovered that injections of salmon fibrin into the damaged spinal cord or rats filled cavities at the injury site and provided the axons with a scaffolding upon which they could grow, reconnect and facilitate recovery. Fibrin produced by the blood system when the blood vessels are breached and it is a fibrous, insoluble protein produced by the blood clotting process.  Surgeons even use it as a kind of surgical glue.

“This is a major next step in our effort to identify treatments that restore functional losses suffered by those with spinal cord injury,” said Steward, professor of anatomy & neurobiology and director of the Reeve-Irvine Research Center. “Paralysis and loss of function from spinal cord injury has been considered irreversible, but our discovery points the way toward a potential therapy to induce regeneration of nerve connections.”

In their study, Steward and Lewandowski subjected rats to spinal cord injuries, and then assessed their defects.  Because these were upper back injuries, the rats all showed impaired forelimb (hand) movement.  Steward and Lewandowski then treated these animals with a combination of salmon fibrin at the site of injury and a modified virus that made a molecule that inhibited PTEN.  These viruses were genetically engineered adenovirus-associated viruses encoded a small RNA that inhibited translation of the PTEN gene (AAVshPTEN).  This greatly decreased the levels of PTEN protein in the neurons.  Other rodents received control treatments of only AAVshPTEN and no salmon fibrin.

The results were remarkable.  Those rats that received the PTEN inhibitor alone showed no improvement in their forelimb function, but those animals who were given AAVshPTEN plus the salmon fibrin recovered forelimb use (at least reaching and grasping).

“The data suggest that the combination of PTEN deletion and salmon fibrin injection into the lesion can significantly enhance motor skills by enabling regenerative growth of corticospinal tract axons,” Steward said.

Corticospinal Nerve tract

Statistics compiled by the Christopher & Dana Reeve Foundation suggests that approximately 2 percent of Americans have some form of paralysis that is the result of a spinal cord injury.  Spinal cord injuries break connections between nerves and muscles or nerves and other nerves.  Even injuries the size of a grape can cause complete loss of function below the level of the injury.  Injuries to the neck can cause paralysis of the arms and legs, an absence of sensation below the shoulders, bladder and bowel incontinence, sexual dysfunction, and secondary health risks such as susceptibility to urinary tract infections, pressure sores and blood clots due to an inability to move one’s legs.

Steward said the next objective is to learn how long after injury this combination treatment can be effectively administered. “It would be a huge step if it could be delivered in the chronic period weeks and months after an injury, but we need to determine this before we can engage in clinical trials,” he said.

Stem Cell-Mediated Scarring of the Spinal Cord Aids in Recovery


After injury to the spinal cord, glial cells and neural stem cells in the spinal cord contribute to the formation of the “glial scar.” This glial scar is rich in molecules known as chondroitin sulfate proteoglycans (CSPGs) that are known to repel growing axons. Therefore, the glial scar is viewed as a major impediment to spinal cord regeneration.

However, new work from the Karolinska Institutet in Solna, Sweden has confirmed that the glial scar actually works to contain the damage within the spinal cord. Far from impairing spinal cord recovery, the stem cell-mediated formation of the glial scar confines the damage to a discrete portion of the spinal cord and prevents it from spreading.

Trauma to the spinal cord can sever those nerve fibers that conduct nerve impulses to from the brain to skeletal muscles below the level of spinal cord injury. Depending on where the spinal cord is injured and the severity of the injury, spinal cord injuries can lead to a various degrees of paralysis. Such paralysis is often permanent, since the severed nerves do not grow back.

The absence of neural regeneration required an explanation, since cultured neurons whose axons are severed can regenerate both in culture and in a living creatures (for an excellent review, see Nishio T. Axonal regeneration and neural network reconstruction in mammalian CNS. J Neurol. 2009 Aug;256 Suppl 3:306-9). Thus, neuroscientists have concluded that the injured spinal contains a variety of molecules that inhibit axonal outgrowth and regeneration.

This hypothesis has been demonstrated since many axon growth inhibitors have been isolated from the injured spinal cord (see Schwab ME (2002) Repairing the injured spinal cord. Science 295:1029–1031). Such molecules include proteins like Nogo, Myelin-Associated Glycoprotein (MAG), and Oligodendrocyte-Myelin Glycoprotein (OMgp). However, as the Nishio review points out, axons from severed nerved have been seen growing throughout the central nervous system. Therefore, most of the blame for a lack of regrowth has been pinned on the glial scar.

A new study by Jonas Frisén of the Department of Cell and Molecular Biology and his colleagues has shown that the neural stem cell population in the spinal cord are the main contributors to the glial scar. However, when glial scar formation was prevented after spinal cord injury, the injured area in the spinal cord expanded and more nerve fibers were severed. Furthermore, in their mouse model, a great number of nerve cells died in those mice that did not make glial scars when compared to those mice that were able to produce a normal glial scar.

Ependymal cell incorporation of 5-ethynyl-2′-deoxyuridine is reduced in the absence of Ras genes in intact spinal cord (A and B) and 7 days after injury (C to E). Arrowheads and arrows point to proliferating recombined (A and C) and unrecombined (C and D) ependymal cells, respectively. Injury-induced migration is blocked in rasless ependymal cells (F). Sagittal view of the lesion site 14 weeks after injury in a FoxJ1 control mouse (G) and FoxJ1-rasless mice (H to J). Recombined ependymal cells express YFP in (A) to (D), and cell nuclei are labeled with 4′,6-diamidino-2-phenylindole (DAPI) and appear blue. *P < 0.05, **P < 0.01; Student’s t test. Error bars show SEM. Scale bars represent 10 μm in (A) to (D) and 200 μm in (G) to (J). GFAP, glial fibrillary acidic protein.
Ependymal cell incorporation of 5-ethynyl-2′-deoxyuridine is reduced in the absence of Ras genes in intact spinal cord (A and B) and 7 days after injury (C to E). Arrowheads and arrows point to proliferating recombined (A and C) and unrecombined (C and D) ependymal cells, respectively. Injury-induced migration is blocked in rasless ependymal cells (F). Sagittal view of the lesion site 14 weeks after injury in a FoxJ1 control mouse (G) and FoxJ1-rasless mice (H to J). Recombined ependymal cells express YFP in (A) to (D), and cell nuclei are labeled with 4′,6-diamidino-2-phenylindole (DAPI) and appear blue. *P < 0.05, **P < 0.01; Student’s t test. Error bars show SEM. Scale bars represent 10 μm in (A) to (D) and 200 μm in (G) to (J). GFAP, glial fibrillary acidic protein.

“It turned out that scarring from stem cells was necessary for stabilizing the injury and preventing it from spreading,” said Frisén. “Scar tissue also facilitated the survival of damaged nerve cells. Our results suggest that more rather than less stem cell scarring could limit the consequences of a spinal cord injury.”

According to earlier animal studies, recovery can be improved by transplanting stem cells to the injured spinal cord. These new findings suggest that stimulating the spinal cord’s own stem cells could offer an alternative to cell transplantation therapies.

This paper appeared in the journal Science, 1 November 2013: 637-640, and the first author was Hanna Sabelström. This interesting paper might be leaving one thing out when it comes to spinal cord regeneration.  Once the acute phase of spinal cord injury is completed and the chronic phase begins, the glial scar does in fact prevent spinal cord regeneration.  This is the main reason Chinese researchers have used chondroitinase enzymes to digest the scar in combination with transplantations on stem cells.  By weakening the repulsive effects of the glial scar, these stem cells can form axons that grow through the scar.  Also, olfactory ensheathing cells or OECs seem to be able to shepherd axons through the scar, although the degree of regeneration with these cells has been modest, but definitely real.  Therefore, negotiating axonal regeneration through the glial scar remains a major challenge of spinal cord injury.  Thus, while the glial scar definitely has short-term benefits, for the purposes or long-term regeneration, it is a barrier all the same.