Researchers at the University of Granada tested decellularized fish scales. They used these scales to create bioartificial corneas. Laboratory and animal tests showed preliminary viability for these replacement tissues.
Corneal disease is a leading cause of reversible blindness globally. An estimated 12 million people need a transplant. Several factors limit the supply of viable donor tissue. Doctors must harvest donor corneas within 24 hours of death. Patients also face the risk of immune rejection. Furthermore, complications like limbal stem cell deficiency can cause transplants to fail over time.
Scientists have explored alternative scaffold materials for years. These materials include synthetic polymers and human-derived collagen. This specific research team previously tested chitosan from crustacean shells. They also evaluated squid gladius structures. The team abandoned the squid materials after observing inflammation during animal testing.
The team gathered scales from common fish in European markets. These included sardine, scorpionfish, salmon, sea bream, and European carp. Researchers used forceps to select appropriate sizes and shapes. Next, they applied detergents and enzymes to remove all fish cells. They washed the scales in a bioreactor. Then, they used acids to remove a thin calcified layer before washing them again. Finally, the team cultured matching corneal cells onto the surface.
Tests showed the fish scale corneas provided necessary mechanical resistance. They also showed enough elasticity to withstand blinking forces. Unlike the earlier squid prototypes, the fish scales prevented inflammation and rejection. The researchers observed that outcomes varied by fish species. They noted differences in scale thickness, transparency, and overall biocompatibility.
The team concluded that fish scales offer a promising scaffold. Food production creates an abundant supply of these scales. This abundance eliminates the need for extra extraction efforts. Prof. Miguel Alaminos researches at the University of Granada. He noted the structural similarities to human tissue.
“The reason why fish scales work so well is because they’re made from a mixture of collagen, hyaluronic acid and products that are in the human body,”
Alaminos said.
“So, it’s no wonder they work very well for us.”
This research remains at an early, preliminary stage. The team has only used laboratory and animal models. They have not conducted any human clinical trials yet. The researchers have not achieved total optical clarity. They currently reach 99 percent transparency instead of 100 percent. The team evaluated only a limited number of fish species. They also have not tested patients with limbal stem cell deficiency.
“it could be years before these fish-derived bioartificial corneas reach a clinical setting.”
As Prof. Alaminos noted,
Reference:
Interview with Prof. Miguel Alaminos and team, Granada Biomedical Research Institute, University of Granada, Spain. Published in BBC Science Focus magazine
