Researchers here make some progress in understanding how stem cell therapies can reduce scarring in a damaged cornea. While focused on injuries rather than age-related damage, this should hopefully still speed progress towards better therapies for a range of conditions that cause blindness through opaque corneal scarring. That the mechanism is keyed to inflammation may also explain why some other approaches known to reduce levels of inflammation, such as those involving mitochondrially targeted antioxidants, are effective.
In cases of severe ocular trauma involving the cornea, wound healing occurs following intervention, but at the cost of opaque scar tissue formation and damaged vision. Recent research has shown that mesenchymal stem cells (MSCs) are capable of returning clarity to scarred corneas; however, the mechanisms by which this happens remained a mystery. Researchers have now identified hepatocyte growth factor (HGF), secreted by MSCs, as the key factor responsible for promoting wound healing and reducing inflammation in preclinical models of corneal injury. Their findings suggest that HGF-based treatments may be effective in restoring vision in patients with severely scarred corneas. "Our results show that mesenchymal stem cells, in an inflamed environment, secrete high levels of HGF, which inhibit scar formation and restore corneal transparency. But if you silence the HGF expression, the stem cells lose their capacity to inhibit scar formation."
Trauma to the eye is the leading cause of corneal opacity, leading to 25 million cases of blindness annually. While injury is not a major cause of blindness, it is one of the most common causes of monocular blindness. Current treatments for corneal scarring vary from topical steroids to corneal transplantation. However, there are limitations to these treatments, including increased risk of infection and rejection of transplants. With the goal of better understanding why MSCs are capable of restoring clarity to scarred corneas, researchers used an animal model of ocular injury. They observed secretion of high levels of HGF from stem cells at the site of injury. Furthermore, the researchers showed that HGF is solely responsible for the restoration of corneal transparency - an observation that holds promise for developing HGF-based therapy for patients.