Publication: Comparison of vascular endothelial growth factor (VEGF) level in tear and serum among age-related macular degeneration (AMD) patients
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Date
2020
Authors
Mohamad, Shahidatul Adha
Journal Title
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Abstract
Introduction:
Vascular endothelial growth factor (VEGF) is believed to play a role in the pathogenesis of agerelated
macular degeneration (AMD). Increased in VEGF level has been known for the
development and progression of AMD. Thus, detection of VEGF level in ocular tissue may
perhaps provide insight into a role of VEGF in pathogenesis of AMD.
Objective:
Our objective was to compare VEGF level in tear and serum between the severity of AMD groups
and to correlate VEGF level between the tear and serum among AMD patients.
Methods:
A comparative cross-sectional study was conducted exclusively at Hospital Universiti Sains
Malaysia (HUSM), a tertiary hospital in the north-east Malaysia, between October 2016 and
October 2018. Gradings of standardized colour fundus photographs according to the Wisconsin
Age-Related Maculopathy Grading System (WARMGS) was used in the study. Patients were
classified into early AMD in the presence of soft indistinct or hard drusen with pigmentary
abnormalities. For late AMD, the graded characteristics are presence of either geographical
atrophy or evidence of exudative features such as serous sensory retinal detachment, subretinal
haemorrhage or subretinal fibrosis; however only exudative type of late AMD was included in this
study. Basal tear fluid was collected without prior stimulation using diagnostic ophthalmic
Schirmer strip. Serum sample was extracted from the blood drawn via venous puncture. Laboratory analysis using commercial Human VEGF ELISA kit (LEGEND MAXTM, Biolegend, Inc.) was
performed to measure VEGF levels in tears and serum. Statistical analysis was done using SPSS
Inc Version 24.
Results:
A total of 108 subjects were included in the study (early AMD: 36 patients, late exudative AMD:
36 patients, control: 36 patients). The study showed mean tear VEGF were significantly higher
among AMD patients (late exudative AMD: 292.88 ± 73.89 pg/ml and early AMD: 161.15 ± 36.73
pg/ml) as compared to control (117.56 ± 16.66 pg/ml, p<0.001). For the mean serum VEGF, it was
significantly higher in late exudative AMD (260.10 ± 76.47 pg/ml) as compared to early AMD
(154.90 ± 39.09 pg/ml, p<0.001) and control (152.11 ± 36.08 pg/ml, p<0.001). There was a
significant linear strong correlation between tear VEGF and serum VEGF level (p<0.001, r=0.795)
among AMD patients.
Conclusion:
This study demonstrates a significant positive correlation between tear and serum VEGF levels in
AMD patients. It also shows that the tear VEGF level correlates with the severity of AMD. Thus,
tear VEGF level measurements can be a good noninvasive method for detection of high-risk early
AMD patients and helpful in monitoring the disease progression. However, a large cohort study is
needed to confirm our results.