Imaging macrophages in human eyes

A label-free imaging technique can illuminate the characteristics of immune cells called macrophages in the eyes of healthy humans and patients with glaucoma, according to a study. Macrophage cells in the retina have typically been examined using labeling techniques and animal models. As a result, little is known about the density, distribution, and movements of these immune cells in the eyes of living humans of various ages, in both healthy and diseased states. Daniel Hammer, Zhuolin Liu, and colleagues used a high-resolution, label-free imaging technique called adaptive optics optical coherence tomography in 15 healthy individuals and four patients with glaucoma, a group of eye diseases that can cause blindness. Cell density decreased with age in healthy participants, by approximately 2% per year between the ages of 20 and 70 years. In patients, cell density was higher on the defective side of the retina, compared with the normal side. Moreover, cell processes moved more quickly and covered a smaller area of the retina in patients compared with healthy participants. The findings suggest that macrophages play a role in the progression of glaucoma, possibly migrating to active areas of disease during early stages. According to the authors, the findings provide a label-free technique to examine retinal macrophages in live human eyes and point to potential biomarkers that could facilitate the development of treatments for glaucoma and other age-related ocular and neurological diseases.

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Article #20-10943: "Label-free adaptive optics imaging of human retinal macrophage distribution and dynamics," by Daniel X. Hammer, Anant Agrawal, Ricardo Villanueva, Osamah Saeedi, and Zhuolin Liu.

MEDIA CONTACTS: Daniel Hammer, United States Food and Drug Administration, Silver Spring, MD; e-mail: <daniel.hammer@fda.hhs.gov>; Zhuolin Liu, United States Food and Drug Administration, Silver Spring, MD; e-mail: <zhuolin.liu@fda.hhs.gov>

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