Novel Surgical Technique Enhances Cell Therapy for Dry Age-Related Macular Degeneration in Animal Studies

Researchers at the National Institutes of Health (NIH) have introduced an innovative surgical method aimed at optimizing cell therapy for dry age-related macular degeneration (AMD), a major contributor to vision impairment among older adults. The findings, published in JCI Insight, highlight the potential of this technique to broaden treatment options for this debilitating condition.

Age-related macular degeneration leads to the deterioration of light-sensitive retina tissue located at the back of the eye. To combat this, scientists are exploring therapeutic strategies that involve transplanting lab-grown tissue grafts derived from patient-specific stem cells to restore damaged retinas.

Historically, surgical procedures have been limited to the implantation of a single graft, restricting the treatment area and impairing comparisons between different graft types in animal models. Such comparisons are essential for validating the integration of grafts with the retina and assessing their interaction with the underlying choriocapillaris, a network of tiny blood vessels that supply nutrients and oxygen to the retina.

To address these limitations, the NIH team developed a specialized surgical clamp that ensures consistent eye pressure during the sequential insertion of two tissue patches, thus minimizing potential damage to adjacent tissues. In their experiments, the researchers employed this advanced technique to implant two distinct grafts within the same AMD-like lesion induced in animal subjects.

The first graft consisted of retinal pigment epithelial (RPE) cells cultivated on a biodegradable scaffold, which plays a crucial role in supporting the retina's photoreceptor cells. The second graft, used as a control, was composed solely of the biodegradable scaffold.

Following the surgical procedure, the scientists utilized artificial intelligence to analyze retinal imaging and assess the efficacy of each graft. Results indicated that RPE grafts significantly enhanced the survival rate of photoreceptors, compared to those adjacent to the scaffold-only grafts, which exhibited a marked increase in cell death.

Moreover, the study confirmed for the first time that the RPE graft not only preserved photoreceptor cells but also facilitated the regeneration of the choriocapillaris, thereby improving the supply of essential nutrients and oxygen to the retina.

These findings build upon the groundwork established in an ongoing NIH-led clinical trial that investigates the application of patient-derived RPE grafts in treating the dry form of AMD.

For further reading, the original study is available in JCI Insight under the title: "iPSC-RPE patch restores photoreceptors and regenerates choriocapillaris in a pig retinal degeneration model."