In the JCI study, he tested this idea by placing sutures in the corneas of two groups of mice to create injuries that would induce a healing response. Then he gave one group of mice a drug to cause macrophages to commit suicide. When he examined the eyes of both groups, he found those given the drug did not grow as many lymph vessels as the control group without the drug.
The implications of this link between macrophages and lymph vessels are far-reaching, according to Stein-Streilein, D'Amore, and Maruyama.
D'Amore and Stein-Streilein believe that harnessing this newly found ability of the macrophages could lead to the creation of new drugs or therapies for eye disease. For instance, inducing new "temporary" lymph vessels in retinas could aid in treating diabetic retinopathy by removing fluids leaking from abnormal blood vessels. It is this leaking fluid, characteristic of diabetic retinopathy that can permanently damage the retina and vision.
Maruyama speculates that the involvement of macrophages in forming lymph vessels may be universal and may also be involved in spreading cancer. If that were the case, blocking macrophages from helping to grow lymph vessels could inhibit the spread of tumors.
The team is now researching the same process in skin wounds and cancer.