RESUMO
Purpose: Tear fluid biomarkers may offer a non-invasive strategy for detecting diabetic patients with increased risk of developing diabetic retinopathy (DR) or increased disease progression, thus helping both improving diagnostic accuracy and understanding the pathophysiology of the disease. Here, we assessed the tear fluid of nondiabetic individuals, diabetic patients with no DR, and diabetic patients with nonproliferative DR (NPDR) or with proliferative DR (PDR) to find putative biomarkers for the diagnosis and staging of DR. Methods: Tear fluid samples were collected using Schirmer test strips from a cohort with 12 controls and 54 Type 2 Diabetes (T2D) patients, and then analyzed using mass spectrometry (MS)-based shotgun proteomics and bead-based multiplex assay. Tear fluid-derived small extracellular vesicles (EVs) were analyzed by transmission electron microscopy, Western Blotting, and nano tracking. Results: Proteomics analysis revealed that among the 682 reliably quantified proteins in tear fluid, 42 and 26 were differentially expressed in NPDR and PDR, respectively, comparing to the control group. Data are available via ProteomeXchange with identifier PXD033101. By multicomparison analyses, we also found significant changes in 32 proteins. Gene ontology (GO) annotations showed that most of these proteins are associated with oxidative stress and small EVs. Indeed, we also found that tear fluid is particularly enriched in small EVs. T2D patients with NPDR have higher IL-2/-5/-18, TNF, MMP-2/-3/-9 concentrations than the controls. In the PDR group, IL-5/-18 and MMP-3/-9 concentrations were significantly higher, whereas IL-13 was lower, compared to the controls. Conclusions: Overall, the results show alterations in tear fluid proteins profile in diabetic patients with retinopathy. Promising candidate biomarkers identified need to be validated in a large sample cohort.
RESUMO
PURPOSE: To evaluate the changes of vascular endothelial growth factor (VEGF) plasma levels after intravitreal injections of ranibizumab or bevacizumab in patients with exudative age-related macular degeneration (AMD). METHODS: Forty-three patients with exudative AMD and 19 age- and sex-matched control patients without chorioretinal diseases were studied. Nineteen patients were treated with intravitreal ranibizumab 0.5 mg, 24 with intravitreal bevacizumab 1.25 mg. Blood samples were collected just before the first injection, and 28 days after three initial consecutive injections performed in 4-weekly intervals (loading dose). Concentration of VEGF in the plasma was measured by ELISA. RESULTS: At baseline, the median VEGF concentrations in controls were 180.97 pg/ml, in the bevacizumab group 189.72 pg/ml and in the ranibizumab group 191.36 pg/ml. VEGF plasma concentrations in patients with wet AMD were comparable to controls (p = 0.225). Twenty-eight days after the third injection, a significant reduction of 42% in the median VEGF plasma levels was found in bevacizumab-treated patients (109.97 pg/ml; p = 0.0002) but not in ranibizumab-treated patients (189.97 pg/ml; p = 0.198) where a reduction of 0.7% in the median value was found. CONCLUSIONS: Intravitreal bevacizumab significantly reduced VEGF plasma levels until 28 days after intravitreal injection in patients with exudative AMD. Ranibizumab did not achieve a significant plasma VEGF reduction at the same time-point. These findings alert to the potential systemic safety differences between the two drugs after intravitreal administration.