Event Review: Stem Cell Therapies - Where Are We?

Stem cell research is one of the most exciting areas of 21st century science. If offers potentially revolutionary ways to repair diseased and damaged body tissues by replacing them with healthy cells. But how close are we to bringing such therapies to the clinic?

This question was the focus for a recent public engagement event jointly hosted by the Association of Medical Research Charities, the London Regenerative Medicine Network and the UK National Stem Cell Network. Over 200 researchers, medical practitioners, funders and enthusiasts gathered at the Wellcome Trust headquarters for what proved to be an stimulating and fascinating evening.

Speakers included Dr Paul de Sousa from the University of Edinburgh and Roslin Cells Ltd; Dr Julie Daniels from University College London (UCL) and Moorfields Eye Hospital, London; Dr John Sinden from ReNeuron Group plc; and Professor Peter Weissberg from the British Heart Foundation.

Dr de Sousa kicked off the discussion by describing work that aims to bridge the gap between embryonic stem cell research and the clinic. It became apparent that this gap has narrowed enough for us to respond to the technological challenges of translational interdisciplinary research and development on stem cell-based therapies.

Questions following his talk included: How can we ensure we fully health-screen stem cell donors? What ethical considerations surround embryonic stem cell sourcing? How can we keep the cells stable after they've spent time in the lab? And how can we guarantee good manufacturing practices? Weighty issues for a cold Monday evening, which could justify an event in themselves!

After Dr de Sousa, we heard from Dr Daniels, whose research concentrates on the clinical applications of stem cell therapy for treating Blinding Ocular Surface diseases. She explained that the cornea, found on the front surface of the eye, is our window to the world. Maintaining our vision is partly dependent on limbal epithelial stem cells (LESCs) residing on the cornea's outermost surface. If these LESCs become damaged, painful blindness can occur.

Her work has produced promising results repairing corneas using amniotic membranes, commonly used in eye surgery, as a transplant substrate for a patient's own cells. But such pioneering work is not without its challenges. Deciding when to bring this to clinical trials presents an ongoing difficulty for Dr Daniels and her team. They must balance the need to help those in need with the latest techniques against the risk of damaging stem cell research's reputation if they trial their work too early.

Dr Daniel's research using LESC therapy has produced some positive initial clinical outcomes. Out of 25 patients who have received treatment, over 60 percent experienced increased vision and reduced pain. Furthermore, treatment appears more successful for those with damaged epithelial cells, for example due to burns, compared to those with the genetic disease Aniridia (absence of the iris). Reasons for this are currently being researched.

Continuing the discussion on pioneering stem cell medical applications was Dr Sinden, whose company ReNeuron administered the world's first fully regulated Phase One clinical trial of a neural stem cell therapy for disabled stroke patients in November 2010. This PISCES (Pilot Investigation of Stem Cells in Stroke) study also became the first to secure regulatory approval for any stem cell-based clinical trial in the UK.

Treatment for stroke typically has three stages, with one being post-stroke rehabilitation. This aims to improve functional and cognitive recovery, and is the focus for ReNeuron's stem cell therapy clinical trial. The cells, named ReN001, reversed stroke disability when injected into the affected region of the brain several weeks after a stroke. Extensive pre-clinical testing also showed the therapy was safe, with the ReN001 cells eventually cleared from the body. Dr Sinden's team are now applying the technology to other conditions, including peripheral arterial disease, retinitis pigmentosa, sub-acute stroke and depression.

The evening's final panellist was Professor Weissberg, Medical Director at the British Heart Foundation (BHF). Their current appeal 'Mending Broken Hearts' has recently hit our TV screens, but how does this relate to stem cell therapies? Professor Weissberg explained that, when a person suffers a heart attack, a portion of their heart muscle is damaged or dies. The human heart is unable to repair itself, but not all creatures are alike. Zebrafish, for example, can regrow damaged parts of their heart.

If heart regeneration is possible in nature, can we find a way to harness key genes and chemical messengers, in the right cells, at the right time, to help our hearts fix themselves? The BHF plans to invest £50 million in stem cell research and developmental biology to investigate this. They hope clinical trials can begin within the next five years.

The event was thought-provoking and insightful, illustrating a few of the latest developments in stem cell therapeutics. These promising research achievements inspired an evening of debate and enthusiastic participation on an emotive topic with serious and complex implications for 21st Century medicine.