Abstract
Purpose :
Intravitreal injections anti-VEGF agents and steroids are currently used for the treatment of diabetic macular edema (DME). However, the selection criteria of the type of treatments are not based on pathophysiological reasons and the response is variable. The main objective of this study was to investigate the usefulness of a panel of cytokines obtained from aqueous humor from patients with DME as predictors of the clinical response after anti-VEGF therapy
Methods :
Aqueous humor (AH) samples obtained prior to anti-VEGF injection from 31 type 2 diabetic patients were analyzed. Patients were classified according anti-VEGF response in 3 groups: rapid responders (n=11), slower responders (n=11), and non-responders (n=9). An additional group (n=7) with a good response to corticosteroids, but with previous failure response to anti-VEGF therapy were included. Clinical response to anti-VEGF was defined according to changes in central retinal thickness (CRT), analyzed by OCT, after 3 monthly intravitreal injection of anti-VEGF as: A) Rapid response: reduction >50% of in CRT. B) Slow response: reduction between 10-50% of CRT at 3 months, but >50% at 6 months. C) No response: < 20% reduction in CRT. Response to corticosteroids was established after the first injection and defined as greater than 50% reduction in CRT at 6-8 weeks. Levels of 17 different cytokines, chemokines, and growth factors (including VEGF and PIGF) in AH were measured using a multiplex immunoassay.
Results :
We found higher levels (pg/ml) of VEGF in AH in rapid responders vs. non-responders (62.2[0-484] vs. 0 [0-75]; p=0.036). In addition, slow-responders to anti-VEGF showed higher levels of inflammatory markers (IL-6, IL-8, TNFR1, TNFR2 and MMP-9) than rapid responders, but did not reach statistical significance. Finally, those patients who responded to corticosteroids but not to anti-VEGF therapy showed a significant lower levels of VEGF than patients with rapid response (0 [0-27] vs. 62.1 [0-484]; p=0.01).
Conclusions :
The use of aqueous humor obtained during the first injection (“liquid biopsy”) could be useful for examining whether the predominant event is the increase of VEGF or other factors. This approach would allow us to select a more rational and probably a most cost-effective treatment. Further studies to validate this preliminary results are warranted.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.