Skin Tissue as a Treatment for Multiple Sclerosis


Italian researchers have derived stem cells from skin cells that can reduce the damage to the nervous system cause by a mouse version of multiple sclerosis. This experiment provides further evidence that stem cells from patients might be a feasible source of material to treat their own maladies.

The principal investigators in this work, Cecilia Laterza and Gianvito Martino, are from the San Raffaele Scientific Institute, Milan and the University of Milan, respectively.

Because multiple sclerosis results from the immune system attacking the myelin sheath that surrounds nerves, most treatments for this disease consist of agents that suppress the immune response against the patient’s own nerves. Unfortunately, these treatments have pronounced side effects, and are not effective in the progressive phases of the disease when damage to the myelin sheath might be widespread.

The symptoms of loss of the myelin sheath might one or more of the following: problems with touch or other such things, muscle cramping and muscle spasms, bladder, bowel, and sexual dysfunction, difficulty saying words because of problems with the muscles that help you talk (dysarthria), lack of voluntary coordination of muscle movements (ataxia), and shaking (tremors), facial weakness or irregular twitching of the facial muscles, double vision, heat intolerance, fatigue and dizziness; exertional exhaustion due to disability, pain, or poor attention span, concentration, memory, and judgment.

Clinically, multiple sclerosis is divided into the following categories on the basis of the frequency of clinical relapses, time to disease progression, and size of the lesions observed on MRI.  These classifications are:

A)         Relapsing-remitting MS (RRMS): Approximately 85% of cases and there are two types – Clinically isolated syndrome (CIS): A single episode of neurologic symptoms, and Benign MS or MS with almost complete remission between relapses and little if any accumulation of physical disability over time.

B)         Secondary progressive MS (SPMS)

C)         Primary progressive MS (PPMS)

D)        Progressive-relapsing MS (PRMS)

The treatment of MS has 2 aspects: immunomodulatory therapy (IMT) for the underlying immune disorder and therapies to relieve or modify symptoms.

To treat acute relapses:

A)    Methylprednisolone (Solu-Medrol) can hasten recovery from an acute exacerbation of MS.

B)    Plasma exchange (plasmapheresis) for severe attacks if steroids are contraindicated or ineffective (short-term only).

C)    Dexamethasone is commonly used for acute transverse myelitis and acute disseminated encephalitis.

For relapsing forms of MS, the US Food and Drug Administration (FDA) include the following:

A)    Interferon beta-1a (Avonex, Rebif)

B)    Interferon beta-1b (Betaseron, Extavia)

C)    Glatiramer acetate (Copaxone)

D)    Natalizumab (Tysabri)

E)    Mitoxantrone

F)    Fingolimod (Gilenya)

G)    Teriflunomide (Aubagio)

H)    Dimethyl fumarate (Tecfidera)

For aggressive MS:

A)    High-dose cyclophosphamide (Cytoxan).

B)    Mitoxantrone

In order to treat multiple sclerosis, restoring the damaged myelin sheath is essential for returning patients to their former wholeness.

In this study, this research team reprogrammed mouse skin cells into induced pluripotent skin cells (iPSCs), and then differentiated them into neural stem cells. Neural stem cells can differentiate into any cell type in the central nervous system.

(a) Bright field image of miPSC-NPCs obtained from miPSC Sox2βgeo. Scale bar, 50 μm. (b) GFP expression on miPSC-NPCs upon LV infection. Scale bar, 50 μm. (c–h) Immunostaining for Nestin (c), Vimentin (d), Olig2 (e), Mash1 (f), Sox2 (g) and GLAST (h). Scale bar, 50 μm. (i) Growth curve of miPSC-NPC. (j–l) Differentiation of miPSC-NPCs in three neural-derived cell populations, neurons (j), astrocytes (k) and oligodendrocytes (l). Scale bar, 50 μm. (m–o) Expression of the adhesion molecule CD44 (m), the chemokine receptor CXCR4 (n) and the integrin VLA-4 (o) on in vitro cultured miPSC-NPCs analysed by flow-activated cell sorting (FACS). Grey line represents the isotype control, whereas red line indicates the stained cells.
(a) Bright field image of miPSC-NPCs obtained from miPSC Sox2βgeo. Scale bar, 50 μm. (b) GFP expression on miPSC-NPCs upon LV infection. Scale bar, 50 μm. (c–h) Immunostaining for Nestin (c), Vimentin (d), Olig2 (e), Mash1 (f), Sox2 (g) and GLAST (h). Scale bar, 50 μm. (i) Growth curve of miPSC-NPC. (j–l) Differentiation of miPSC-NPCs in three neural-derived cell populations, neurons (j), astrocytes (k) and oligodendrocytes (l). Scale bar, 50 μm. (m–o) Expression of the adhesion molecule CD44 (m), the chemokine receptor CXCR4 (n) and the integrin VLA-4 (o) on in vitro cultured miPSC-NPCs analysed by flow-activated cell sorting (FACS). Grey line represents the isotype control, whereas red line indicates the stained cells.

Next, Laterza and her colleagues administered these neural stem/progenitor cells “intrathecally,” which simply means that they were injected into the spinal cord underneath the meninges that cover the brain and spinal cord to mice that had a rodent version of multiples sclerosis called EAE or experimental autoimmune encephalomyelitis.

EAE mice are made by injecting them with an extract of myelin sheath. The mouse immune system mounts and immune response against this injected material and attacks the myelin sheath that surrounds the nerves. EAE does not exactly mirror multiple sclerosis in humans, but it comes pretty close. While multiple sclerosis does not usually kill its patients, EAE either kills animals or leaves them with permanent disabilities. Animals with EAE also suffer severe nerve inflammation, which is distinct from multiple sclerosis in humans in which some nerves suffer inflammation and others do not. Finally, the time course of EAE is entirely different from multiple sclerosis. However, both conditions are caused by an immune response against the myelin sheath that strips the myelin sheath from the nerves.

The transplanted neural stem cells reduced the inflammation within the central nervous system. Also, they promoted healing and the production of new myelin. However, most of the new myelin was not made by the injected stem cells. Instead the injected stem cells secreted a compound called “leukemia inhibitory factor” that promotes the survival, differentiation and the remyelination capacity of both internal oligodendrocyte precursors and mature oligodendrocytes (these are the cells that make the myelin sheath). The early preservation of tissue integrity in the spinal cord limited the damage to the blood–brain barrier damage. Damage to the blood-brain barrier allows immune cells to infiltrate the central nervous system and destroy nerves. By preserving the integrity of the blood-brain barrier, the injected neural stem cells prevented infiltration of blood-borne of the white blood cells that are ultimately responsible for demyelination and axonal damage.

(a) EAE clinical score of miPSC-NPC- (black dots) and sham-treated mice (white dots). Each point represents the mean disease score of at least 10 mice per group (±s.e.m.); two-way ANOVA; *P<0.05; **P<0.01. (b) Quantification of spinal cord demyelination and axonal damage at 80 dpi in miPSC-NPC- (black bars) versus sham-treated (white bars) EAE mice (N=6 per group). Data (mean values ±s.e.m.) represent the percentage of damage. Student’s t-test; *P<0.05; **P<0.01. (c,d) Representative images of spinal cord sections stained with Luxol Fast Blue (c) and Bielschowsky (d). Red dotted lines represent areas of damage. Scale bar, 200 μm. (e) Quantitative analysis of the localization of miPSC-NPCs upon transplantation into EAE mice (N=3). (f–k) Immunostaining for CD45, MBP, Nestin, Ki67, Olig2, GFAP, βIII tubulin and GFP shows accumulation of transplanted cells (arrowheads) within perivascular spinal cord damaged areas. Dotted lines represent vessels. Nuclei are visualized with DAPI. Scale bars, 50 μm. (l) Percentage (±s.e.m.) of the miPSC-NPCs expressing the different neural differentiation markers upon transplantation into EAE mice; the majority of transplanted miPSC-NPCs remained undifferentiated. (N=3 mice per group).
(a) EAE clinical score of miPSC-NPC- (black dots) and sham-treated mice (white dots). Each point represents the mean disease score of at least 10 mice per group (±s.e.m.); two-way ANOVA; *P<0.05; **P

“Our discovery opens new therapeutic possibilities for multiple sclerosis patients because it might target the damage to myelin and nerves itself,” said Martino.

Timothy Coetzee, chief research officer of the National Multiple Sclerosis Society, said of this work: “This is an important step for stem cell therapeutics. The hope is that skin or other cells from individuals with MS could one day be used as a source for reparative stem cells, which could then be transplanted back into the patient without the complications of graft rejection.”

Obviously, more work is needed, but this type of research demonstrates the safety and feasibility of regenerative treatments that might help restore lost function.

Martino added, “There is still a long way to go before reaching clinical applications but we are getting there. We hope that our work will contribute to widen the therapeutic opportunities stem cells can offer to patients with multiple sclerosis.”

See Cecilia Laterza, et al. iPSC-derived neural precursors exert a neuroprotective role in immune-mediated demyelination via the secretion of LIF. NATURE COMMUNICATIONS 4, 2597: doi:10.1038/ncomms3597.

Benefits of stem cells in treating MS declines with donor’s age


MS is a neurodegenerative disease characterized by inflammation and scar-like lesions throughout the central nervous system (CNS). There is no cure and no treatment eases the severe forms of MS. But previous studies on animals have shown that transplantation of mesenchymal stem cells (MSCs) holds promise as a therapy for all forms of MS (see Bai L, et al., Glia 2009 Aug 15;57(11):1192-203). The MSCs migrate to areas of damage, release trophic (cell growth) factors and exert protective effects on nerves and regulatory effects to inhibit T cell proliferation.

Several clinical trials examining the ability of fat-derived MSCs to treat MS patients have been conducted. Unfortunately, most of these studies are rather small and the results are all over the place. One study treated ten patients with MSCs injected intrathecally (just under the meninges that cover the brain and spinal cord) and the results were mixed; 6/10 improved, 3 stayed the same and one deteriorated. Another study treated ten patients with intravenous fat-derived MSCs and the patients showed symptomatic improvement, but when MRIs of the brain were examined, no improvements could be documented. A third study treated 15 people with intrathecal injections and IV administrations of MSCs, and some stabilized. A fourth study only examined 3 patients treated with a mixture of their own fat-derived MSCs and fat-derived MSCs from another person. In all three cases, their MRIs and symptoms improved. A fifth study used umbilical cord MSCs administered intravenously and the patient showed substantial improvement (for review see Tyndall, Pediatric Research 71(4):433-438).

These results are somewhat encouraging, but also somewhat underwhelming and clinical trials go. Why did some work and other not work as well? In order to understand why, researchers must understand the biologic changes and therapeutic effects of older donor stem cells. A new study appearing in the journal STEM CELLS Translational Medicine is the first to demonstrate that adipose-derived MSCs donated by older people are less effective than cells from their younger counterparts.

Fortunately, all the available MS-related clinical trials have confirmed the safety of autologous MSC therapy. As to the efficacy of these cells, however, it is unclear if MSCs derived from older donors have the same therapeutic potential as those from younger ones.

“Aging is known to have a negative impact on the regenerative capacity of most tissues, and human MSCs are susceptible to biologic aging including changes in differentiation potential, proliferation ability and gene expression. These age-related differences may affect the ability of older donor cells to migrate extensively, provide trophic support, persist long-term and promote repair mechanisms,” said Bruce Bunnell, Ph.D., of Tulane University’s Center for Stem Cell Research and Regenerative Medicine. He served as lead author of the study, conducted by a team composed of his colleagues at Tulane.

In their study, Bunnell and his colleagues induced an MS-like disease in laboratory mice called chronic experimental autoimmune encephalomyelitis (EAE). Then they treated them before disease onset with human adipose-derived MSCs derived from younger (less than 35 years) or older (over age 60) donors. The results corroborated previous studies that suggested that older donors are less effective than their younger counterparts.

“We found that, in vitro, the stem cells from the older donors failed to ameliorate the neurodegeneration associated with EAE. Mice treated with older donor cells had increased inflammation of the central nervous system, demyelination leading to an impairment in movement, cognition and other functions dependent on nerves, and a proliferation of splenocytes [white blood cells in the spleen], compared to the mice receiving cells from younger donors,” Dr. Bunnell noted.

In fact, the proliferation of T cells (immune cells that attack the myelin sheath in MS patients) in these mice indicated that older MSCs might actually stimulate the proliferation of the T cells, while younger stem cells inhibit T cell proliferation. T cells are a type of white blood cell in the body’s immune system that help fight off disease and harmful substances. When they attack our own tissues, they can cause diseases like MS.

As such, Dr. Bunnell said, “A decrease in T cell proliferation would result in a decreased number of T cells available to attack the CNS in the mice, which directly supports the results showing that the CNS damage and inflammation is less severe in the young MSC-treated mice than in the old MSC-treated mice.”

“This study in an animal model of MS is the first to demonstrate that fat-derived stem cells from older human donors have less therapeutic effectiveness than cells from young donors,” said Anthony Atala, M.D., editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “The results point to a potential need to evaluate cell therapy protocols for late-onset multiple sclerosis patients.”