Tear Martix Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinase-1 in Post-Lasik Ectasia.

PURPOSE: To estimate the concentrations of matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinase-1 (TIMP-1) in the tear film of cases with post-Lasik ectasia (PLE) to spot any role of these mediators. SETTINGS: Ophthalmology department, Benha University hospitals, Egypt. METHODS: Twelve eyes of 12 patients with PLE, 30 eyes of 30 patients with KC, 25 eyes of 25 subjects with uncomplicated Lasik and finally 25 eyes of 25 healthy subjects as a control group were studied. Subjects with ocular surface diseases, previous ocular surgeries except for Lasik in PLE group and Lasik group, were excluded. All subjects had full ophthalmic examination and Pentacam imaging. The concentration of tear MMP-9 and TIMP-1 was measured by ELISA. RESULTS: Our results showed a significant elevation in the level of MMP-9 and a significant reduction in the level of TIMP-1 in tear samples from PLE cases (MMP-9 was 59.17 ± 28.15 ng/ml, and TIMP-1 was 110.3 ± 50.6 ng/ml) and also in KC cases (MMP-9 was 53.12 ± 17.35 ng/ml, and TIMP-1 was 105.8 ± 56.3 ng/ml) when compared to post-Lasik group (MMP-9 was 35.65 ± 17.32 ng/ml, and TIMP-1 was 155.2 ± 39.4 ng/ml) and control group (MMP-9 was 31.92 ± 20.78 ng/ml, and TIMP-1 was 162.5 ± 48.2 ng/ml). CONCLUSION: The results pointed to potential role of MMP-9 in the pathogenesis of PLE and also referred to a biochemical similarity between PLE and KC. More studies are needed in the future to investigate larger number of tear mediators.

MicroRNAs (-146a, -21 and -34a) are diagnostic and prognostic biomarkers for diabetic retinopathy.

BACKGROUND: Diabetic retinopathy (DR) is implicated in blindness of diabetic patients. Early diagnosis of DR is very essential to ensure good prognosis. The role of microRNAs (miRs) as biomarker diagnostic tools in DR is not fully investigated. The present study aimed to find the relation between serum relative expression of microRNAs (miR-146a, miR-21 and miR-34a) and severity of DR and to what extent their expression pattern can be used as either diagnostic or prognostic. METHODS: Eighty type 2 diabetic patients were classified according to severity of DR into normal, mild, moderate, severe non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). Serum relative expressions of miRNAs were evaluated by qPCR and statistically analysed in each stage using Analysis of Variance (ANOVA) followed by Tuckey-Kramer post-test. RESULTS: Serum relative expressions of miR-146a and miR-21 were increased with increased severity of DR. miR-34a decreased with the severity of DR. The expression pattern in each group in relation to normal fundus group could be diagnostic and prognostic where miR-146a was only increased in mild group and continued with the severity. In moderate group miR-21 start to increase along with slight decrease in miR-34a. In severe NPDR group along with highly increased levels of both miR-146a and miR-21, a marked decrease in miR-34a. In PDR group miR-34a was almost diminished along with very high levels of both miR-146a and miR-21. CONCLUSIONS: miRs (-146a,-21 and-34a) are promising biomarkers in DR and can help to avoid disease progression.