Experimental therapy shows adverse effects

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In the last decade there has been great hopes that stem cells, which are considered as “all-rounders”, would offer a treatment for spinal cord injury. While these hopes are still alive, one must not neglect that cell therapies need to be tested thoroughly.  

There has always been concerns and warning that stem cells, which can transform into many cell types, could just as easily transform into an unwanted issue or even worse create tumors. Nevertheless many patients underwent unproven cell therapies.

Ten years ago an experimental treatment with “olfactory mucosal cells” was carried out as part of an early stage trial in the Hospital de Egas Moniz in Lisbon, Portugal. Wings for Life did not fund this treatment. One patient enrolled in this early stage trial was a young, 18 year old paraplegic, receiving autologous olfactory mucosal cell implantation. Olfactory mucosa contains stem-like progenitor cells and olfactory ensheathing cells (OECs), both cell types are thought to mediate repair of the central nervous system.

The patient had no benefit from this experimental treatment. Eight years later she started complaining of worsening back pain that had already been ongoing for a year. Scans at the University of Iowa Hospitals and Clinics revealed a mass on the spinal cord, at the site of the cell implantation, the pressure against the spinal cord was causing the discomfort. Upon extraction, the team could confirm a tumor generated from the olfactory mucosal cells implanted eight years earlier.

The medical team from the University of Iowa Hospitals and Clinics that removed and investigated the growth has reported the anomaly in a paper published in the Journal of Neurosurgery: Spine.

What went wrong for this patient, and what can be learned from this?  

First the authors point out, that such result should not deter scientists and clinicians from stem cell research and clinical trials.
But with regard to safety one can conclude that a) there is still a need for better understanding of how to control cell proliferation in the pathological environment and 

b) the use of more purified stem cells or pre-differentiated cells with an already restricted growth potentialmay be safer and

c) a longer follow-up time of cell based intervention studies  is needed to assess the real risk for the patient’s health

The recommendation for patients who consider to join an experimental study are complied the following guide: Experimental treatments for spinal cord injury: what you should know if you are considering participation in a clinical trial. Download here.