Cone fusion confusion in photoreceptor transplantation

Transplanted Donor- or Stem Cell-Derived Cone Photoreceptors Can Both Integrate and Undergo Material Transfer in an Environment-Dependent Manner

“…Previously, we reported that manipulation of the immune system prolonged the presence of GFP + cells in the wild-type host ONL ( West et al., 2010 ), a finding that can be, perhaps, alternatively explained by prolonging the survival of donor cells available to provide material for transfer. Similarly, two other recent reports reported that modulation of the host immune environment permitted sustained survival of transplanted cells in the SRS ( Zhu et al., 2017 , Neves et al., 2016 ), and, from our interpretation of the published images, what appears to include robust levels of material transfer (see also MacLaren, 2017 ). The dependency on donor developmental stage and the apparent need for the sustained presence of donor cells may provide clues as to the cellular mechanisms underlying material transfer.…”

Outer Retinal Cell Replacement: Putting the Pieces Together

“… 152 – 156 In a subsequent transplant study by Waldron et al, nearly all GFP+ cells (99%) found in wildtype host retinas and most GFP+ cells (>75%) in degenerative Nrl − / − and Prph2 rd2/rd2 retinas were estimated to result from material transfer, 157 calling the results of several previous rodent studies into question. 72 , 76 , 82 , 88 , 123 , 145 , 158 Although the exact mechanism and longevity of this phenomenon remains to be determined, at present, several points are clear. First, material transfer is more likely to occur in degenerating retinas with remaining host PRs 152 – 156 than in models of end-stage retinal degeneration.…”

Sensory Transduction in Photoreceptors and Olfactory Sensory Neurons: Common Features and Distinct Characteristics

“…Cell therapy consists of the transplantation of cells derived from embryonic or induced stem cells, or from retinal organoids, where it is possible to determine the developmental stage of the cells to transplant. One promising approach is the transplant of ectopic retinal pigmented epithelial cells (Schwartz et al, 2015;Mandai et al, 2017), in comparison to the transplant of photoreceptors, which is still lagging behind (Pearson et al, 2012;MacLaren, 2017;Ribeiro et al, 2021).…”