Regenerative medicine specialist Dr Darius Widera debunks claims that autism can be treated with stem cell therapy and asks whether autism needs to be ‘cured’ at all in a recent post for The Conversation.
The outlook for autistic people today is brighter than it was 50 years ago with many people now living in the community, rather than in institutions. But most low-functioning autistic people are not able to live independently in adulthood, putting them and their families under considerable social and financial pressure. So it’s hardly surprising that some parents of autistic children are keen to find a treatment for the condition. According to a recent BBC Radio 4 report, stem cell clinics in the UK are now offering one.
Before we look at the viability of such a “treatment”, it is worth knowing a bit about stem cells. Stem cells are special cells that can develop into many types of cell, such as liver cells, blood cells or nerve cells. In the early developing embryo, stem cells can develop into any cell type, but stem cells in adults have a much more limited capability.
Adult stem cells can only develop into cell types of the organ they originate from. For example, stem cells originating from the bone marrow can only give rise to closely related cell types, such as fat, cartilage and bone cells, while stem cells in the brain can only differentiate into brain cells.
Stem cell therapies aim at regenerating or replacing cells that are affected by disorders and diseases. This can be achieved by isolating stem cells from the patient or a donor and turning them into the desired cells in a laboratory before transplanting them in the patient.
In an alternative approach, stem cells can be transplanted without differentiating them outside of the patient’s body in the hope that the tissue will dictate their fate. This idea is based on the assumption that every tissue contains specific signal molecules telling the stem cells what to become.
A successful stem cell therapy relies on at least two things. First, the tissue and cell type affected by disease or disorder must be known. Second, the right stem adult cell type or early so-called pluripotent cells must be applied. If a disease is caused by degeneration of brain tissue, a cell type able to replace the nerve cells lost due to the condition needs to be used. If the target is bone tissue, a stem cell type that can replace bone cells should be applied. So a one-size-fits-all approach is unlikely to work.
Under-regulated stem cell clinics
The promise of stem cell therapies to tackle disorders with limited conventional treatment options has led to the development of a considerable industry offering stem cell therapies.
Initially limited to developing countries, the number of under-regulated stem cell clinics is growing in developed countries, including the US, Germany, Switzerland and the UK. Most of these businesses are using a loophole in the law which allows the use of stem cells isolated from the patient’s own body (so-called autologous transplantation) for debilitating conditions that cannot be treated with existing drugs. In contrast, all other stem cell therapies must undergo thorough assessments for quality, safety and efficacy.
With an autologous approach, most stem cell clinics use cells isolated from the patient’s bone marrow or fat tissue. Although these cells are unable to generate any cell types apart from fat, bone cells or cartilage, many of the stem cell clinics offer treatments for a range of conditions, including dementia, cerebral palsy and autism. These therapies aren’t supported by scientific evidence and they are expensive – around £10,000.The procedure usually involves isolating cells from the bone marrow or fat tissue of the patient and injecting the cells back into the bloodstream with the hope that the transplanted cells migrate to the organ affected by the disease. Once in the target tissue, stem cells could contribute to regeneration by replacing the faulty cells or by boosting the internal repair capability of the body.
Although some common genetic and environmental factors have been identified in autism, little is known about the exact type of nerve cells affected. Indeed, recent research published in the journal Science suggests that, in addition to nerve cells, microglia (a cell type that fulfils an immune function in the brain) could be affected in people with autism.
This cellular complexity in autism makes designing a stem cell treatment more than challenging. What cell types need to be replaced? Is it enough to boost the patient’s own repair capability? Even if these open questions would be addressed in the future, what stem cell type needs to be used? Is it viable to use adult stem cells or are more potent pluripotent cells needed? So, at least today, autism cannot be treated with stem cells.
An even more fundamental question has been discussed by autism activist groups: does autism need to be cured at all or is it just a form of neurodiversity that society should embrace?
This post first appeared on The Conversation, 21 January 2020. Dr Darius Widera is Associate Professor in Stem Cell Biology and Regenerative Medicine at the University of Reading. His areas of expertise are adult stem cells, expansion of stem cells for their clinical use, and the role of inflammation in health and disease.