A patient taking part in a clinical trial of an induced pluripotent stem cell treatment for age-related macular degeneration has experienced an adverse effect, the Japan Times reports.
The patient, who is in his 70s, received a transplant of retinal cells derived from donor iPS cells to treat his age-related macular degeneration, the paper adds. The Japan News notes that the clinical trial, consisting of five patients, began in March.
After treatment, the patient's retina became swollen, leading him to have surgery earlier this week in the hopes of relieving the swelling, as steroids and anti-vascular endothelial growth factors didn't diminish his symptoms, the Japan Times says. The team removed his pre-retinal membrane and his symptoms improved, it adds
Masayo Takahashi, the Riken researcher who heads the team conducting the trial, said at a news conference earlier this week that "[w]e cannot deny the causal correlation with iPS cells."
Takahashi first tested this technique in 2014 when an 80-year-old Japanese woman received retinal pigment epithelium cells that were developed from reprogrammed skin cells. The Japan Times says the new patient is the first to experience an adverse reaction to the treatment.
But University College London's Mike Cheetham tells New Scientist that the swelling was probably due to the original surgery, not the iPS cells.