Stem Cell Therapy - Spina Bifida and Hydrocephalus

Stem Cells.  What are they?  What do they do? and why might you be interested? 

Read below for more information.

What are stem cells? 

Stem cells are cells which have not yet become specialised to form various tissues. In an embryo, all the cells are stem cells, they’re a bit like balls of clay that can be turned into lots of different things. Most stem cells change to become specialised for a certain function, such as neurons or red blood cells. This process, called differentiation, is how we get specialist cells such as neurons (nerve cells) or red blood cells. In adults, stem cells can be found in some organs and tissues, for example, the brain, blood, and bone marrow. Unlike fetal stem cells that can become any type of cell, adult stem cells are a bit more restricted and can only become types of cell related to the site they’re found. Fat cells contain a type of stem cell for connective tissue, mesenchymal stem cells. 

Why is there so much interest in stem cells? 

Because stem cells can turn into different types of cells, there is a potential for them to repair damaged tissues or replace cells that are not working well (for example in bone marrow transplants for blood disorders).  

What stem cell research is being done in spina bifida and hydrocephalus? 

Blood from the umbilical cord is rich in blood-producing stem cells, and this can be stored in a ‘bank’. In the UK, The NHS Blood and Transplant Service can store donated cord blood, which may be used if people develop blood disorders such as leukaemia. There are also private banks, which will store cord blood if you wish to reserve it for your family members, rather than donating it for public use. 

Information about spina bifida

For several years, a project in the USA led by Diana Farmer, has looked at using stem cells to help repair the damage to exposed spinal tissue in myelomeningocoele. After successful treatment of bulldog puppies with spina bifida a clinical trial has started. The plan is to place a scaffold of mesenchymal stem cells over the open area of the spinal cord during fetal surgery and see if the cells can repair the spinal tissue.  The surgery is performed at around 25-26 weeks of pregnancy, to protect the spinal cord from severe and irreversible damage that occurs in the third trimester.  The stem cells can be introduced before this damage occurs, while the baby is still growing and developing rapidly. As well as the structural effect of the stem cells, it is hoped they will also secrete proteins and growth factors to promote healing. You can read more about the study here and in this journal article. 

This approach is less likely to be successful in older children or adults, though there have been cell therapy studies in acquired spinal cord injury. When the spinal cord is damaged a type of ‘nerve scar’ forms, to prevent the wrong nerves connecting with each other during healing. But some therapies have helped the coating around nerves, (myelin) which enable the signals to be transmitted faster, to regenerate after the damage. 

A clinical trial in people with spinal cord injuries is underway at the moment. The first phase showed one person recovered a significant degree of movement and sensation, but others had modest improvement, and others none at all. Researchers are continuing to investigate why some people respond better than others to stem cell treatments. One factor that may need to be considered in spina bifida is that because the condition begins before birth, the nerve pathways joining the body to the specific parts of the brain (body map) does not form completely, so trying to link these up in later life may be more complicated than in spinal injury. Read more here. 

Some very interesting work is being done in the use of stem cells to support children with neuropathic bladders. At the moment, the bladder may need to be enlarged using part of the bowel. Although this works well, it does have its downsides, with mucus production, changes to the blood chemistry, and a small additional risk of cancer. Using the body’s own stem cells to ‘grow’ extra bladder tissue has been looked at with promising results so far.  In animal experiments, stem cells formed bladder tissue, and blood vessels and nerve cells, which will be essential for healthy bladder tissue to be generated. This article has more information about the use of stem cells in bladder regeneration. 

Stem cell therapy research is an expanding field that offers considerable promise in modern medicine, providing hope for a number of future treatments that may be of benefit in spina bifida and/or hydrocephalus.

Information about Hydrocephalus

There have been a few case reports of babies with congenital hydrocephalus being given transfusions of their own cord blood, to try to improve the oxygen-carrying potential of the blood, and so aid healing. Although the cases suggested the procedure was safe, there’s no information regarding whether it helps with hydrocephalus. 

Hydrocephalus that begins before birth starts with changes very early on in the pregnancy.  There is a combination of changes to the brain development and to the flow of CSF. Shunting helps to control the rising pressure but doesn’t reverse changes to the brain development that can result in lifelong learning and behaviour challenges. In recent years, research looking at those changes has found that the lining of the ventricles and Aqueduct of Sylvius (the narrow channel between the third and fourth ventricles) begins to detach, exposing the brain tissue to the CSF. This leads to disruption of the growing brain cells: fewer cells divide and migrate towards the surface of the brain, and some cells can form clumps known as periventricular heterotopia. These clumps can become a focus for seizures. The changes are often genetic, although the same sequence of changes is seen after infection or bleeding. Losing the lining causes the aqueduct to collapse and block (aqueduct stenosis), increasing the pressures inside the ventriclesThis further prevents CSF, with its important chemical messengers, from reaching parts of the brain where it’s needed. 

For a number of years researchers have used animal models to see if implanting the stem cells that brain cells grow from into the ventricles at birth can help repair the lining. These “neural stem cells” as they are known, seem to begin to replace the damaged lining and to start healing damaged areas of the brain. This article explains the research well.  

One area for possible development in the future is to transplant neural stem cells into the ventricles of babies having prenatal surgery for spina bifida. 

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