Stem cell therapies hold promise, but obstacles remain

August 22, 2014 by Mark Michaud, University of Rochester Medical Center
Stem Cell Therapies Hold Promise, But Obstacles Remain

(Medical Xpress)—In an article appearing online today in the journal Science, a group of researchers, including University of Rochester neurologist Steve Goldman, M.D., Ph.D., review the potential and challenges facing the scientific community as therapies involving stem cells move closer to reality. 

The review article focuses on (PSCs), which are stem cells that can give rise to all cell types. These include both , and those derived from that have been "reprogrammed" or "induced" – a process typically involving a patient's own – so that they possess the characteristics of found at the earliest stage of development.  These cells can then be differentiated, through careful manipulation of chemical and genetic signaling, to become virtually any cell type found in the body. 

While the process of making induced PSCs is relatively new in scientific terms – it was first demonstrated that skin cells could be successfully reprogrammed in 2007 – one of the reasons that these cells are viewed with promise by the scientific community is because they are derived from the patient's own tissue. Consequently, cells used for transplant can be a genetic match and far less likely to be rejected, thereby potentially mitigating the need to use immune system suppressing drugs. 

The article addresses the current state of efforts to apply PSCs to treat a number of diseases, including diabetes, liver disease, and heart disease. Goldman, a distinguished professor and co-director of the University of Rochester School of Medicine and Dentistry Center for Translational Neuromedicine, reviewed the current state of therapies for

While progress has been made over the last several years, the authors point out that significant challenges remain. Scientists must be able to obtain the precise cell populations required to treat the target disease, and once transplanted, make sure that these cells get to where they are needed and integrate into existing tissue. The cells that are transplanted must also first be checked for purity and screened for unwanted cells that could give rise to tumors. 

Goldman and his co-authors contend that "the brain is arguable the most difficult of the organs in which to employ stem cell-based therapeutics."   The complex connections and interdependency between neurons and the myriad of other support cells found in central nervous mean that a precise reconstruction of damaged areas of the brain is often impractical. Also, many degenerative neurological disorders, including Alzheimer's, involve more than one cell type, making them difficult targets for , at least in the near future.

Instead, Goldman argues that neurological diseases that involve a single cell type – at least at the early stages – are more promising targets for PSC-based therapies. These include Parkinson's disease and Huntington's disease, which are characterized by the loss of dopamine-producing neurons and medium spiny neurons, respectively.  In particular, diseases that involved support cells found in the brain known as glia – such as multiple sclerosis, white matter stroke, cerebral palsy, and pediatric leukodystrophies – are especially strong candidates for stem cell therapies. These diseases are characterized by the loss of a specific glial cell type called the oligodendrocyte, which makes myelin, the insulation that allows electrical signals to travel between nerve cells. In multiple sclerosis, the body's own immune system attacks and destroys these cells and, over time, communication between cells is disrupted or even lost.

Oligodendrocytes are the offspring of another cell called the oligodendrocyte progenitor cell, or OPC.  Scientists have long speculated that, if successfully transplanted into the diseased or injured brain, OPCs might be able to produce new oligodendrocytes capable of restoring lost myelin, thereby reversing the damage caused by these diseases. 

Goldman's group has already shown that OPCs produced from PSCs obtained from successfully restore myelin in the brains and spinal cords of myelin-deficient mice, and can rescue and restore function to mice that would have otherwise died.  While this work demonstrated the promise of stem cell therapies, it also illustrated the challenges facing scientists. It took Goldman's lab four years to establish the exact chemical signaling required to reprogram, produce, and ultimately purify OPCs in sufficient quantities for transplantation, and only recently has the group developed methods for producing the in purity and quantity sufficient to transplant into humans.

The authors contend that future progress will depend upon continued close collaboration between scientists and clinicians, and between academia, industry and regulatory bodies to overcome the remaining barriers to bringing new stem cell-based therapies to patients with these devastating diseases.

Explore further: Cells forged from human skin show promise in treating multiple sclerosis, myelin disorders

Related Stories

Cells forged from human skin show promise in treating multiple sclerosis, myelin disorders

February 7, 2013
A study out today in the journal Cell Stem Cell shows that human brain cells created by reprogramming skin cells are highly effective in treating myelin disorders, a family of diseases that includes multiple sclerosis and ...

Scientists 1 step closer to cell therapy for multiple sclerosis patients

July 24, 2014
Scientists at The New York Stem Cell Foundation (NYSCF) Research Institute are one step closer to creating a viable cell replacement therapy for multiple sclerosis from a patient's own cells.

'Master switch' for myelination in human brain stem cells is identified

June 30, 2014
Scientists at the University at Buffalo have identified the single transcription factor or "master switch" that initiates the critical myelination process in the brain. The research will be published online in Proceedings ...

Implanted neurons become part of the brain

August 4, 2014
Scientists at the Luxembourg Centre for Systems Biomedicine (LCSB) of the University of Luxembourg have grafted neurons reprogrammed from skin cells into the brains of mice for the first time with long-term stability. Six ...

Researchers at the doorstep of stem cell therapies for MS, other myelin disorders

October 25, 2012
When the era of regenerative medicine dawned more than three decades ago, the potential to replenish populations of cells destroyed by disease was seen by many as the next medical revolution. However, what followed turned ...

Recommended for you

More surprises about blood development—and a possible lead for making lymphocytes

January 22, 2018
Hematopoietic stem cells (HSCs) have long been regarded as the granddaddy of all blood cells. After we are born, these multipotent cells give rise to all our cell lineages: lymphoid, myeloid and erythroid cells. Hematologists ...

How metal scaffolds enhance the bone healing process

January 22, 2018
A new study shows how mechanically optimized constructs known as titanium-mesh scaffolds can optimize bone regeneration. The induction of bone regeneration is of importance when treating large bone defects. As demonstrated ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

Weight flux alters molecular profile, study finds

January 17, 2018
The human body undergoes dramatic changes during even short periods of weight gain and loss, according to a study led by researchers at the Stanford University School of Medicine.

Secrets of longevity protein revealed in new study

January 17, 2018
Named after the Greek goddess who spun the thread of life, Klotho proteins play an important role in the regulation of longevity and metabolism. In a recent Yale-led study, researchers revealed the three-dimensional structure ...

The HLF gene protects blood stem cells by maintaining them in a resting state

January 17, 2018
The HLF gene is necessary for maintaining blood stem cells in a resting state, which is crucial for ensuring normal blood production. This has been shown by a new research study from Lund University in Sweden published in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.