The growing field of autologous stem-cell therapy has set its sights on another potential ocular target: corneal dystrophies.
A Spanish and Lebanese research team has completed a phase 1 pilot study demonstrating that autologous adipose-derived stem cells (ADSCs) can survive transplantation into the corneal stroma and produce new collagen. The investigative therapy is designed to strengthen and repair the cornea in patients with keratoconus and other diseases involving dysfunctional corneal keratocytes.
Following promising results in animal models, the treatment paradigm was assessed in 5 adult patients with advanced keratoconus.
“This study suggests that ADSCs can be implanted, that the procedure is safe and that ADSCs produce new, healthy collagen in the diseased eyes,” said principle investigator Jorge L. Alió del Barrio, MD, PhD, who published his findings in the August 2017 issue of Cornea.
For the first step of the trial, ADSCs were retrieved from the adipose tissue of each patient via liposuction. When the cultured cells were ready, a 9.5-mm corneal incision was made using a femtosecond laser with the patient under topical anesthesia. The surgeons then used a cannula to transfer 3 million cells through the lamellar pocket into the stroma.
The researchers chose to use mesenchymal ADSCs due to their capability to differentiate into many cell types and their easy accessibility compared with other stem cell sources. Though improper and poorly executed use of ADSCs to treat ocular diseases has made headlines in recent months, the safety profile thus far appears excellent.
Following the 10-minute implantation procedure, no inflammation or episodes of rejection were noted. And despite concern over perforating an already thin and weakened cornea, the team observed no adverse effects on corneal biomechanics. The patients’ corneas appeared completely clear within 48 hours, suggesting that neither the ADSCs nor the procedure induces opacification and that the new keratocytes produce clear collagen.
Six months after treatment, 4 patients showed a mean UCVA improvement of 1 line, and BCVA increased by 2 lines with rigid contact lens. Visual data was not available for the 5th subject, who did not complete the full follow-up evaluation. In all subjects, IOP and endothelial cell density remained stable, and confocal biomicroscopy confirmed the survival of the implanted stem cells at the surgical plane. Refractive sphere improved in 2 participants and remained at baseline in 3 participants.
“Now we need a longer follow-up to see the therapeutic benefits of this new collagen and its impact on the natural progression of the disease,” Alió said. “In the long term, these keratocytes should be able to take over and compensate the defect created by the diseased keratocytes, maybe reestablishing corneal thickness.”