Age is a risk factor for cardiovascular disease (CVD), however the effect of age on platelet function remains unclear. Ideally, platelet function should be assayed under flow and shear conditions that occur in vivo. Our study aimed to characterise the effect of age on platelet translocation behaviour using a novel flow-based assay that measures platelet function in less than 200 μl of blood under conditions of arterial shear. Blood from males (n = 53) and females (n = 56), ranging in age from 19–82 and 21–70 respectively were perfused through custom-made parallel plate flow chambers coated with immobilised human von Willebrand Factor (VWF) under arterial shear (1,500s−1). Platelet translocation behaviour on VWF was recorded by digital-image microscopy and analysed. The study showed that aging resulted in a significant decrease in the number of platelet tracks, translocating platelets and unstable platelet interactions with VWF. These age related changes in platelet function were more profound in women than in men indicating that age and gender significantly impacts on platelet interactions with VWF.
Background Very low birth weight (VLBW) preterm neonates have an increased risk of hemorrhage-related morbidity and mortality as compared with their full-term counterparts. It is unclear whether platelet function differs between preterm and full-term neonates. This is partly because of the large volumes of blood required to perform standard platelet function tests, and the difficulty in obtaining such samples in neonates. Objectives This study was designed to characterize platelet behavior in neonates with a physiologic flow-based assay that quantifies platelet function in microliter volumes of blood under arterial shear. Methods Blood from VLBW preterm neonates of ≤ 32 weeks' gestation (n = 15) and full-term neonates (n = 13) was perfused under arterial shear over surface-immobilized von Willebrand factor (VWF). Platelet behavior was recorded by digital-image microscopy and analyzed. Surface expression of platelet glycoprotein (GP) Ibα and GPIIIa of VLBW preterm and full-term neonates was also measured. Results VLBW preterm neonates had increased numbers of platelets interacting with VWF, and increased GPIbα expression on the platelet surface. Despite the increased numbers of VWF interactions as reflected by flow-driven platelet translocation along the protein surface, no significant differences were observed in the numbers of platelets that adhered in a stationary fashion to VWF. Platelets from VLBW preterm neonates and those from full-term neonates behaved differently on VWF. Conclusions These differences in platelet function may contribute to the higher incidence of bleeding observed in VLBW preterm neonatal populations, or may represent a compensatory mechanism to counteract this risk of bleeding.
Platelet function in pregnancy is poorly understood. Previous studies of platelet function in pregnancy have used non-physiological assays of platelet function with conflicting results. This study using a physiological assay of platelet function investigated platelet interactions with von Willebrand Factor (VWF) in blood from healthy pregnant women and healthy non-pregnant controls. Blood samples (200 µl) from third-trimester pregnancies (n = 21) and non-pregnant controls (n = 21) were perfused through custom-made parallel-plate flow chambers coated with VWF under arterial shear (1,500 s−1). Multi-parameter measurements of platelet interactions with the immobilized VWF surface were recorded by digital-image microscopy and analysed using custom-designed platelet-tracking software. Platelet interactions with VWF decreased in healthy third-trimester pregnant participants relative to controls. This effect is most likely due to haemodilution which occurs physiologically during pregnancy. Interestingly, platelets in blood from pregnant participants translocated more slowly on VWF under arterial-shear conditions. These decreases in platelet translocation speed were independent of haemodilution, suggesting intrinsic changes in platelet function with pregnancy.
<b><i>Objective:</i></b> Studies summarizing the outcome of first-trimester septated cystic hygroma are generally based on small studies or from multiple centers with limited ascertainment. We reviewed the natural history of a large cohort of such cases from a single tertiary referral center, with the aim being to establish contemporary outcome data, particularly in the setting of normal karyotype. <b><i>Methods:</i></b> A retrospective cohort study from 2007 to 2017 was conducted at a single tertiary referral prenatal diagnosis center. Data were analyzed from a prospectively collated fetal anomaly database. Search terms were “increased nuchal translucency (NT),” “cystic hygroma,” and “septated cystic hygroma.” All cases were confirmed to have NT >3 mm with septations. Cases of simple increased NT without septations were excluded. <b><i>Results:</i></b> During the study period, over 110,000 pregnancies were delivered at our center, resulting in 410 cases of septated cystic hygroma diagnosed prior to 14 weeks’ gestation. Pregnancy outcome was obtained in 99% (405/410) of cases, with detailed pathology outcome available in 92% (378/410). A total of 87% (351/405) underwent invasive prenatal testing, and postnatal chromosome status was established in further 27 cases. A total of 61% (230/378) had abnormal chromosomal status. Of the 39% (148/378) with normal chromosomal status, only 13% (19/148) had a significant structural fetal abnormality, which included 7 cardiac and 12 noncardiac abnormalities. Overall, the perinatal loss was 62% (253/405). The total survival rate in the setting of euploid cystic hygroma without structural abnormality was 84% (108/129). <b><i>Conclusions:</i></b> Counseling regarding outcomes in the setting of first-trimester septated cystic hygroma initially focuses on the strong likelihood of an abnormal karyotype, which occurs in 61% of cases. However, once fetal chromosomal abnormality is excluded, our results demonstrate only a 13% incidence of major structural fetal abnormality, which appears significantly less than previously reported. Normal fetuses have a 77% survival rate. These data represent the largest single-center study of first-trimester cystic hygroma with complete outcome data and therefore will be useful for contemporary patient counseling. Such counseling can be more positive than previously expected, once chromosomal abnormality is first excluded.
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