Beyond hemostasis and thrombosis, an increasing number of studies indicate that platelets play an integral role in intercellular communication, mediating inflammatory and immunomodulatory activities. Our knowledge about how platelets modulate inflammatory and immunity has greatly improved in recent years. In this review, we discuss recent advances in the pathways of platelet activation and potential application of platelet activation biomarkers to diagnosis and prediction of disease states.

BackgroundAngiogenesis is a multistep process in which many growth factors and cytokines have an essential role. Vascular endothelial growth factor (VEGF) is a potent angiogenic agent that acts as a specific mitogen for vascular endothelial cells through specific cell surface receptors. The interleukin-6 (IL-6) pathway is another mechanism linking angiogenesis to malignancy. C-reactive protein (CRP), a representative marker for inflammation, is known for its association with disease progression in many cancer types. The aim of this study was to determine preoperative serum levels of VEGF, IL-6, and CRP in colorectal carcinoma, and to correlate them with disease status and prognosis.MethodsA 132 of 143 patients who underwent curative resection for colorectal cancer were enrolled in this study. 11 patients with resection margin positive were excluded. Factors considered in analysis of the relationship between VEGF, IL-6, and CRP and histological findings. Patient prognosis was investigated. Serum levels of VEGF and IL-6 were assessed using Enzyme-Linked Immuno-Sorbent Assay (ELISA), and CRP was measured using immunoturbidimetry.ResultsMedian follow-up duration was 18.53 months (range 0.73-43.17 months) and median age of the patients was 62 years (range, 26-83 years). Mean and median levels of VEGF and CRP in colorectal cancer were significantly higher than in the normal control group; 608 vs. 334 pg/mL and 528 (range 122-3242) vs. 312 (range 16-1121) (p < 0.001); 1.05 mg/dL vs. 0.43 mg/dL and 0.22 (range 0.00-18.40) vs. 0.07 (range 0.02-6.94) (p = 0.002), respectively. However mean and median level of IL-6 in patients were not significantly higher than in control; 14.33 pg/mL vs. 5.65 pg/mL and 6.00 (range 1.02-139.17) vs. 5.30 (4.50-13.78) (p = 0.327). Although IL-6 and CRP levels were not correlated with other pathological findings, VEGF level was significantly correlated with tumor size (p = 0.012) and CEA (p = 0.038). When we established the cutoff value for VEGF (825 pg/mL), IL-6 (8.09 pg/mL), and CRP (0.51 mg/dL) by Receiver Operating Characteristic (ROC) curve, we noted that high VEGF levels tended to reduce overall survival (p = 0.053), but not significantly. However, IL-6 and CRP demonstrated no significance with regard to disease free survival (p = 0.531, p = 0.701, respectively) and overall survival (p = 0.563, p = 0.572, respectively). Multivariate analysis showed that VEGF (p = 0.032), CEA (p = 0.012), lymph node metastasis (p = 0.002), and TNM stage (p = 0.025) were independently associated with overall survival.ConclusionsPreoperative serum VEGF and CRP level increased in colorectal cancer patients. High VEGF level has been proposed as a poor prognostic factor for overall survival in patients with colorectal cancer.

BackgroundAn association has been reported between CYP2C19 polymorphism and the altered antiplatelet activity of clopidogrel. We investigated this association using the newly introduced platelet function analyzer (PFA)-200 (INNOVANCE PFA-200 System; Siemens Healthcare, Germany) P2Y test.MethodsPolymorphisms of CYP2C19*2, *3, *17 and the degree of inhibition of platelet function were determined in 83 patients. Three different platelet function tests were used to evaluate the degree of platelet inhibition and to check the association with genotype.ResultsThe post-procedure PFA-200 values of extensive metabolizers (EM) patients (285.3±38.8) were higher than those of intermediate metabolizers (IM) and poor metabolizers (PM) patients (227.7±98.3 and 133.7±99.2, respectively; P=0.024). Light transmittance aggregometry (LTA) and the VerifyNow system showed that the post-procedure values for EM patients were lower than those of IM and PM patients (LTA: 24.4±15.7, 34.1±17.6, and 42.2±16.9, respectively, P<0.001; VerifyNow: 133.2±60.5, 171.5±42.6, and 218.7±59.3, respectively, P<0.001). The high residual platelet reactivity (HPR) rates were significantly different among the EM, IM, and PM groups using PFA-200 (PM:IM:EM=82.4:40.6:11.8, P<0.001).ConclusionsApproximately, 59.0% of Korean patients with cardiovascular disease receiving clopidogrel had CYP2C19 loss-of-function genotypes classified as IM or PM, and the frequency was similar to the data from Asian people. The PFA-200, LTA, and VerifyNow platelet function tests revealed evidence of a significant association between the efficacy of clopidogrel and CYP2C19 genotypes.

Aspirin reduces the prevalence of nonfatal myocardial infarction, stroke, and death by 25.0% in high risk group of patients with cardiovascular disease. Previous studies have estimated that about 5.5-56.8% of the population are aspirin resistant. The mechanisms of aspirin resistance (AR) have not been fully understood. We compared the detection methods for AR using traditional platelet aggregometry and VerifyNow system. One hundred and seventy-two coronary artery disease patients who had taken aspirin only or combinations with aspirin and clopidogrel for over 7 days were included. Of the 55 patients with aspirin only, aggregometer detected six AR (10.9%) and VerifyNow identified 10 AR (18.2%) cases. Among 117 patients with combined therapy, none (0.0%) and 10 (8.5%) of AR were detected by aggregometer and VerifyNow, respectively. There were six (3.4%) patients of AR defined by both methods and they all received aspirin monotherapy. Although the correlation between the aggregometry and VerifyNow was low, with defined criteria both methods gave 91.9% agreement to find AR. VerifyNow showed a higher sensitivity to detect AR. Further studies are required to biologically define AR and to alter therapy based on platelet function tests.

Background: Detection of antiphospholipid antibodies (aPL) can be considered problematic due to assay variability and reagent sensitivity, high false-positive and false-negative rates, and lack of assay standardization. Therefore, utilizing an automated system can improve reproducibility and reduce interlaboratory variation. Here, we evaluated the analytical performance of the new automated ACL AcuStar chemiluminescence assay (Instrumentation Laboratory, USA). This was compared to the results of a panel analyzed with the QUANTA Lite ELISA (INOVA Diagnostics Inc., USA). Methods:We evaluated the inter-assay precision, linearity, and carry-over between the two methods, ACL and ELISA. A reference range study for each of the anticardiolipin (aCL) and anti-b 2 glycoprotein-I (ab 2 GPI) IgG and IgM antibodies were performed using 135 healthy patient samples, which served as controls. We then compared the accuracy among the AcuStar and ELISA systems via four aPL tests. For this comparison, 69 patient samples suspected of an autoimmune disorder were used as the experimental panel. Results:The AcuStar analyzer showed excellent precision, linearity, and carry-over for all four assays. The calculated cutoff values were 20.3 U/mL for aCL IgG, 20.3 U/mL for aCL IgM, 26.3 U/mL for ab 2 GPI IgG, and 11.9 U/mL for ab 2 GPI IgM. The consensus between AcuStar and ELISA results were generally comparable. Total agreement varied between 82.6% and 95.7%, and kappa values showed moderate to good agreement. Conclusions: Our study demonstrates that the new AcuStar chemiluminescence assay showed better performance. This automated system leads to improved reproducibility and reduces interlaboratory variability. (J Lab Med Qual Assur 2015;37:134-140)