Relationship between serum and tear levels of tissue plasminogen activator and plasminogen activator inhibitor-1 in diabetic retinopathy

• Published in: BMC Ophthalmology
• Main Author: Jasmiad N.; Abd Ghani R.; Agarwal R.; Ismail Z.; Mohd Abdullah A.A.; Idorus M.Y.
• Format: Article
• Language: English
• Published: BioMed Central Ltd 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85137159329&doi=10.1186%2fs12886-022-02550-4&partnerID=40&md5=e9e326cc009fc90c6a46b7a53575be18

Background: Diabetic retinopathy (DR) is a serious complication of longstanding type 2 diabetes mellitus (T2DM), a leading cause of blindness and visual disability in the world. The aim of this study is to compare the activity of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) in tears and serum of patients with DR and those without DR. Method: Among the T2DM patients enrolled in this study, 26 patients had DR (n = 26) while 29 were without DR (n = 29). The blood and tear samples were obtained from all participants. The level of PAI-1 and tPA were measured in both the serum and tears. Anthropometric measurements, HbA1c, renal and lipid profile were also obtained. Results: Patients with DR had significantly longer disease duration and higher systolic blood pressure compared to those without DR. Serum PAI-1 level was significantly higher in patients with DR compared to those without DR, 32.72 (IQR 32.52) vs 21.37 (IQR 14.93) ng/mL, respectively (p < 0.05). However, tear PAI-1 were comparable in both groups. Serum and tear tPA levels in both groups were also comparable (p > 0.05). Among patients with DR, there were no significant correlations between tear and serum of both biomarkers. Patients without DR showed a moderate positive correlation between serum and tear tPA levels with a coefficient of 0.363, albeit no statistical significance. Patients with DR demonstrated a significant positive correlation between levels of tears PAI-1 and BMI (r = 0.555, p = 0.026). In the group without DR, there was a statistically significant positive correlation between serum level of PAI-1 with urine albumin creatinine ratio (UACR) (r = 0.501, p = 0.013). Conclusion: The present study demonstrated a significantly greater serum PAI-1 levels in patients with DR compared to those without DR. No significant correlations between tears and serum PAI-1 and tPA were observed. Thus, the role of tear biomarkers remains relevant for further investigations. © 2022, The Author(s).