Can Rotational Thromboelastometry be a New Predictive Tool for Retinal Vein Occlusion Development?

Platelet Proteome Reveals Novel Targets for Hypercoagulation in Pseudoexfoliation Syndrome

Pseudoexfoliation syndrome (PEX) is characterized by the accumulation of abnormal extracellular matrix material in ocular and non-ocular tissues, including blood vessel walls. Clot-forming dysfunction might be responsible for venous thrombosis in PEX. We investigated global coagulation, the proteome, and functions of platelets in PEX patients and aimed to determine prognostic biomarkers for thrombosis risk in PEX. Peripheral blood was collected from PEX and retinal vein occlusion (RVO) patients, and age-sex matched controls. Viscoelastic hemostasis was evaluated by rotational thromboelastometry (ROTEM). Platelet markers (CD41, CD42, CD61, and CD62p) and endothelial markers (P-selectin, E-selectin, and von Willebrand factor) were investigated by flow cytometry and ELISA, respectively. The platelet proteome was analyzed by 2D fluorescence difference gel electrophoresis followed by mass spectrometry. Clot formation time (CFT) is significantly reduced in PEX patients compared to the controls (p < 0.05). P-selectin levels were higher in PEX patients than in controls (p < 0.05); E-selectin and von Willebrand factor remained unchanged. The monitorization of CFT by ROTEM, and soluble P-selectin, may help assess thrombotic risk in PEX patients. Proteomic analysis revealed differential expression of Profilin-1 in platelets. Profilin-1 regulates the stability of actin-cytoskeleton and may contribute to impaired platelet hemostatic functions. Increased P-selectin levels together with impaired coagulation dynamics might be responsible for the thrombotic events in PEX disease.

Relation Between Platelet Reactivity Levels and Diabetic Retinopathy Stage in Patient with Type 2 Diabetes Mellitus by Using Multiplate Whole Blood Aggregometry

Purpose: To test the hypothesis of a possible association between platelet reactivity and the severity of diabetic retinopathy using Multiplate whole blood aggregometry in type 2 diabetes mellitus patients. Methods: Of 157 patients were divided to three groups based on the severity of diabetic retinopathy (normal, non-proliferative and proliferative [ordinal among group 1-2-3]). Platelet reactivity was measured using arachidonic acid response to the ASPI and ADP platelet test. The association between DR stage and the degree of platelet reactivity (predictor variable) ASPI, ADP, systolic blood pressure, age, hypertension, body mass index (BMI), HbA1c, creatinine, Microalbumin, platelet, triglyceride/HDL and Hscrp variables were evaluated using ordinal logistic regression models (Model 1). The association between DR presence (outcome variable (group 1 vs group 2 and 3)) and the presence of variables was evaluated using binary logistic regression models (Model 2). Results: A comparison of the laboratory parameters of the three groups revealed that the ASPI, ADP, glucose and HbA1c values were significantly higher in Group-3 than Group-1. ASPI (odds-ratio OR: 1.044[1.021-1.09], p < .001], ADP (OR: 1.033[1.010-1.10], p: 0.002] and HbA1c (OR: 2.42(1.22, 4.94), p < .001) were demonstrated to be associated with stage of DR while the other variables were not. In binary logistic regression (model-2) analysis; ASPI (OR: 1.061[1.031-1.1], p < .001], ADP (OR: 1.03(1.01, 1.06), p: 0.045] and HbA1c (OR: 4.37 (1.67, 11.36)], p: 0.002) were associated with DR while the other variables were not. Conclusion: Herewith, we demonstrated that higher platelet reactivity measured by multiplate ASPI and ADP was significantly associated with stages of DR. Therefore, these measurements may be useful to predict the severity of DR in the clinical practice of physicians.

ASSOCIATION BETWEEN PLATELET INDICES AND RETINAL VEIN OCCLUSION: A Systematic Review and Meta-Analysis

PURPOSE

Platelet count, mean platelet volume, platelet distribution width, and plateletcrit are standard indices of platelet activation that have been studied in retinal vein occlusion (RVO) and its subtypes: branch retinal vein occlusion and central retinal vein occlusion. This systematic review and meta-analysis aimed to assess the association between these platelet parameters and RVO.

METHODS

We searched for studies investigating the association between these platelet indices and RVO in multiple online databases from inception to August 2020. Mean differences and the associated confidence intervals were obtained and calculated for each included study and pooled using random-effects inverse variance modeling. Meta-regression was used to explore interstudy and intrastudy heterogeneity.

RESULTS

Thousand three hundred and twenty-five unique studies were screened, from which 24 studies encompassing 2,718 patients were included. Mean platelet volume and platelet distribution width were significantly elevated in RVO, with pooled mean differences of 0.45 fL (95% CI 0.24-0.66, P < 0.0001) and 1.43% (95% CI 0.57-2.29, P = 0.0011), respectively. Platelet count and plateletcrit were not significantly associated with RVO. Mean platelet volume was also independently elevated in branch retinal vein occlusion and central retinal vein occlusion.

CONCLUSION

Mean platelet volume and platelet distribution width are significantly elevated in RVO. Further research is required to explore the independence and potential prognostic significance of these associations.

Technology Advancements in Blood Coagulation Measurements for Point-of-Care Diagnostic Testing

In recent years, blood coagulation monitoring has become crucial to diagnosing causes of hemorrhages, developing anticoagulant drugs, assessing bleeding risk in extensive surgery procedures and dialysis, and investigating the efficacy of hemostatic therapies. In this regard, advanced technologies such as microfluidics, fluorescent microscopy, electrochemical sensing, photoacoustic detection, and micro/nano electromechanical systems (MEMS/NEMS) have been employed to develop highly accurate, robust, and cost-effective point of care (POC) devices. These devices measure electrochemical, optical, and mechanical parameters of clotting blood. Which can be correlated to light transmission/scattering, electrical impedance, and viscoelastic properties. In this regard, this paper discusses the working principles of blood coagulation monitoring, physical and sensing parameters in different technologies. In addition, we discussed the recent progress in developing nanomaterials for blood coagulation detection and treatments which opens up new area of controlling and monitoring of coagulation at the same time in the future. Moreover, commercial products, future trends/challenges in blood coagulation monitoring including novel anticoagulant therapies, multiplexed sensing platforms, and the application of artificial intelligence in diagnosis and monitoring have been included.