Stem cell-derived retinal patch continues to show promising results two years post-implantation

Earlier this year we wrote about the promising results of a phase 1 clinical trial aimed at replacing the deteriorating cells in the retinas of people suffering from age-related macular degeneration- one of the leading causes of blindness worldwide for people over 50. Now there’s even more good news! Highlighted in a news story on the UC Santa Barbara (UCSB) website, researchers are continuing to make progress in their bid to secure approval from the Food and Drug Administration for the life-changing treatment.

Through the collaborative efforts of researchers at UCSB, University of Southern California and California Institute of Technology, a stem cell-derived implant using cells from a healthy donor was developed. The bioengineered implant, described as a scaffold, was then implanted under the retina of 16 participants. If the implant was to work, the new cells would then take up the functions of the old ones, and slow down or prevent further deterioration. In the best-case scenario, they could restore some lost vision.

The first sets of trials, funded by the California Institute for Regenerative Medicine (CIRM), concentrated on establishing the safety of the patch and collecting data on its effectiveness. Parting ways with old practices, the participants in the trial were given just two months of immunosuppressants whereas in the past, using donor cells meant that patients often had to be given long-term immunosuppression to stop their body’s immune system attacking and destroying the implanted cells. The team found that after two years, the presence of the patch hadn’t triggered other conditions associated with implantation, such as the formation of new blood vessels or scar tissue that could cause a detachment of the retina.

Even more importantly, they found no sign of inflammation that indicated an immune response to the foreign cells even after the patient was taken off immunosuppressants two months post-implantation. “What really makes us excited is that there is some strong evidence to show that the cells are still there two years after implantation and they’re still functional,” said Mohamed Faynus, a graduate student researcher in the lab of stem cell biologist Dennis O. Clegg at UCSB.

Having passed the initial phase, the team of researchers now hopes to begin phase 2 of the trial. This time, they are aiming to more specifically assesses the effectiveness of the patch in participants. Looking even farther ahead, the Clegg Lab and colleagues are also exploring combining multiple cell types on the patch to treat patients at varying stages of the disease.

In addition, there have also been improvements made to extend the shelf life of the patch. “Cryopreservation of the therapy significantly extends the product’s shelf-life and allows us to ship the implant on demand all over the world, thus making it more accessible to patients across the globe,” said Britney Pennington, a research scientist in the Clegg Lab.

3 thoughts on “Stem cell-derived retinal patch continues to show promising results two years post-implantation

  1. Could this also b effective with retinitis pigmentosa or just macular degeneration? Asking for a friend Karen

    Sent from my iPhone


    • Theoretically it could also help people with RP, if they used the cells that are being destroyed by RP. For now it’s only the cells attacked by AMD.

  2. Cells require specific growth factor to bind to their cellular receptors. The binding of receptor-ligand complex generate intracellular stimulus which is recognized and processed by signal tranduction systems. This resulted a number of defined changes in cytoplasmic biochemistry to mediate proliferative activity, differantiation state, or behavior. The deprived of specific growth factor may trigger the cells become growth arrest. However, other growth factors are needed to support short-term survival of cells. Almost all of the cells in humans body systems produce a variety of growth factors, suggesting that growth factors in environmental of cell can support cell survival, development and behavior in vivo.

    Current clinical trial with donor stem cell -derived retinal patch showed that the implanted stem cells can survive for 2 year without triggering immune rejection. Results of 2 years follow up was conducted on 15 patients showed : 1)4 patients improved version in the treated eyes. The ability of humans produce growth factors in their bodies systems are varying. Stem cells require specific growth factors for maturation. The process of maturation involves many stages of development and each stage of maturation response to different growth factors. The above mentioned patients only had abilities to produce some some specific growth factors to support partially maturation leading to improve their vision after 2 years of implantation. Stem cells require full range of specific growth factors to develop into mature and fully functional RPE cells, in order to fully restore the vision of patients. The earlier stage of progenitors do not developed restriction antigen respond towards foreign body systems and hence no immune rejection were observed. 2)5 patients experienced stabilization of their vision. Those patients did not have ability to produce any specific growth factor to support maturation of RPE cells. Their bodies can only produce growth factors to support the survival of stem cells in patch. 3)6 patients with their vision acutely continued to decline. Those patients bodies systems did not produce sufficient growth factors to support the survival of stem cells in patch.

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