Believe it or not, glaucoma is the most common cause of irreversible blindness across the globe. In total, it is estimated that nearly 80 million people worldwide have glaucoma, a figure that is projected to increase to over 110 million by 2040. Despite these troublesome facts, there might be some hope for those at risk of developing this condition.

At Second Sight

This good news comes in the form of a study issued by the prestigious Harvard Medical School. Publishing their work in the journal Nature, this group was successfully able to reprogram nerve cells in the eyes of mice. Consequently, the rodents’ vision quickly improved, to the point that their vision rivaled that of younger mice. Considering that these mice were suffering from a glaucoma-like condition, this was quite a noteworthy accomplishment. 

So how did the Harvard team pull this off? Strange as it might sound, the study authors relied on an adeno-associated virus (AAV) to restore the mice’s vision. The AAV acted as a sort of conduit, transporting a total of three genes – known as Oct4, Sox2 and Klf4 – into the rodents. Collectively, the three injected genes are commonly referred to as Yamakan factors. 

The results of this experiment were noteworthy for multiple reasons. For example, the team noted significant nerve regeneration among mice with previously damaged optic nerves. Furthermore, mice suffering from a glaucoma-like condition likewise experienced an improvement in vision. Even older mice with no indication of glaucoma exhibited improved vision following the gene injections.

Off and On

A new aging theory provided the inspiration for the Harvard team’s approach. While the function of a particular cell varies, the majority of the cells in our body have the same set of DNA molecules. In order to work properly, our cells must have the ability to only read specific types of genes. 

The system that controls this process is known as the epigenome, which is tasked with activating and deactivating genes in certain patterns. According to this new theory, over time the epigenome becomes less capable of fulfilling its role, leading to disease and the usual signs of aging. Using the aforementioned trio of cells, the Harvard team aimed to undo this damage. 

The study’s senior author, Yuancheng Lu, was highly encouraged by his team’s work. “At the beginning of this project, many of our colleagues said our approach would fail or would be too dangerous to ever be used,” said Lu. “Our results suggest this method is safe and could potentially revolutionize the treatment of the eye and many other organs affected by aging.”