Aqueous humour concentrations of TGF-β, PLGF and FGF-1 and total retinal blood flow in patients with early non-proliferative diabetic retinopathy.

Abstract

With great interest, we read the article ‘Aqueous humour concentrations of TGF-β, PLGF and FGF-1 and total retinal blood flow (TRBF) in patients with early non-proliferative diabetic retinopathy (NPDR)’ (Khuu et al. 2016). The authors aimed to correlate angiogenic cytokines in the aqueous humour with TRBF in subjects with type 2 diabetes with NPDR. They found that non-invasive measurement of TRBF may be useful for predicting aqueous FGF-1 levels and severity of vasculopathy in diabetic retinopathy (DR). We congratulate the authors for their excellent work. We would like to make some contributions and criticisms related to this study. (i) According to our experience (Du et al. 2016), cytokine concentrations in aqueous humour may be not in parametric distribution. Therefore, nonparametric test (e.g., Mann–Whitney U-test) should be more appropriate for analysing the aqueous humour concentrations of cytokines between control and NPDR groups. (ii) In the subject demographics of study population, the heart rate between the two groups is significantly different. As heart rate is one of important factors influencing retinal blood flow (Burgansky-Eliash et al. 2013), it should be adjusted in the analysis of TRBF. (iii) Because the use of ocular or systemic drugs may have a major influence on the aqueous humour concentrations of cytokines and blood flow, the authors should provide more details about whether these patients were using any drugs when these factors were recorded and how long these drugs were taken. We hope that addition of information about the above-mentioned issues might help us to reach more definitive conclusions in this study.