-Original-

Brain-derived Neurotrophic Factor in the Aqueous Humor of Glaucoma Patients

Tsutomu Igarashi¹, Kenji Nakamoto¹, Maika Kobayashi¹, Hisaharu Suzuki¹, Takeshi Arima¹, Yutaro Tobita¹, Kazuhiro Takao¹, Toru Igarashi², Takahisa Okuda³, Takashi Okada⁴ and Hiroshi Takahashi¹

¹Department of Ophthalmology, Nippon Medical School, Tokyo, Japan
²Department of Pediatrics, Nippon Medical School, Tokyo, Japan
³Division of Legal Medicine, Department of Social Medicine, Nihon University School of Medicine, Tokyo, Japan
⁴Division of Molecular and Medical Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan

Background: Brain-derived neurotrophic factor (BDNF) may be involved in the pathogenesis of glaucoma. BDNF concentrations reported in previous studies have varied widely, and the concentration of BDNF in aqueous humor is unknown. In this study, BDNF concentrations in the aqueous humor of glaucoma patients and control patients were measured with ELISA kits.
Methods: This prospective, observational study examined BDNF levels in aqueous humor in 62 eyes of 43 patients who underwent cataract surgery or trabeculectomy (11 glaucoma patients and 32 non-glaucoma cataract patients as controls). BDNF concentrations were examined by 4 different enzyme-linked immunosorbent assay (ELISA) techniques.
Results: The mean ± SD patient age was 72.0 ± 10.1 (range 35 to 87) years. Two of the techniques detected no BDNF in aqueous humor in any samples (n=3 and n=9, respectively); the average value was less than zero. An ultrasensitive ELISA kit did not yield reliable measurements. Finally, in an even more sensitive ELISA (Simoa-HD1), performed by an outside contractor, 25 (54.3%) eyes were below the detection limit, including 20 (55.6%) control and 5 (50%) glaucoma cases. For eyes with detectable BDNF, the overall BDNF concentration was 0.158 pg/mL (n=21): 0.196 pg/mL (n=16) in controls and 0.034 pg/mL (n=5) in glaucoma cases.
Conclusions: BDNF level in aqueous humor varies widely.

J Nippon Med Sch 2021; 88: 128-132

Keywords
brain-derived neurotrophic factor, BDNF, glaucoma, aqueous humor, anterior chamber

Correspondence to
Tsutomu Igarashi, MD, PhD, Department of Ophthalmology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
tutomu@nms.ac.jp

Received, March 21, 2020
Accepted, May 1, 2020