Salivary tissue factor induces thrombin generation in a diurnal rhythm

Circadian misalignment disrupts biomarkers of cardiovascular disease risk and promotes a hypercoagulable state

The circadian system regulates 24-h time-of-day patterns of cardiovascular physiology, with circadian misalignment resulting in adverse cardiovascular risk. Although many proteins in the coagulation-fibrinolysis axis show 24-h time-of-day patterns, it is not understood if these temporal patterns are regulated by circadian or behavioral (e.g., sleep and food intake) cycles, or how circadian misalignment influences these patterns. Thus, we utilized a night shiftwork protocol to analyze circadian versus behavioral cycle regulation of 238 plasma proteins linked to cardiovascular physiology. Six healthy men aged 26.2 ± 5.6 years (mean ± SD) completed the protocol involving two baseline days with 8-h nighttime sleep opportunities (circadian alignment), a transition to shiftwork day, followed by 2 days of simulated night shiftwork with 8-h daytime sleep opportunities (circadian misalignment). Plasma was collected for proteomics every 4 h across 24 h during baseline and during daytime sleep and the second night shift. Cosinor analyses identified proteins with circadian or behavioral cycle-regulated 24-h time-of-day patterns. Five proteins were circadian regulated (plasminogen activator inhibitor-1, angiopoietin-2, insulin-like growth factor binding protein-4, follistatin-related protein-3, and endoplasmic reticulum resident protein-29). No cardiovascular-related proteins showed regulation by behavioral cycles. Within the coagulation pathway, circadian misalignment decreased tissue factor pathway inhibitor, increased tissue factor, and induced a 24-h time-of-day pattern in coagulation factor VII (all FDR < 0.10). Such changes in protein abundance are consistent with changes observed in hypercoagulable states. Our analyses identify circadian regulation of proteins involved in cardiovascular physiology and indicate that acute circadian misalignment could promote a hypercoagulable state, possibly contributing to elevated cardiovascular disease risk among shift workers.

Extracellular Vesicles in Liquid Biopsies: Potential for Disease Diagnosis

Liquid biopsy is conducted through minimally invasive or noninvasive procedures, and the resulting material can be subjected to genomic, proteomic, and lipidomic analyses for early diagnosis of cancers and other diseases. Extracellular vesicles (EVs), one kind of promising tool for liquid biopsy, are nanosized bilayer particles that are secreted by all kinds of cells and that carry cargoes such as lipids, proteins, and nucleic acids, protecting them from enzymatic degradation in the extracellular environment. In this review, we provide a comprehensive introduction to the properties and applications of EVs, including their biogenesis, contents, sample collection, isolation, and applications in diagnostics based on liquid biopsy.

Human milk triggers coagulation via tissue factor-exposing extracellular vesicles

Almost a century ago, it was discovered that human milk activates the coagulation system, but the milk component that triggers coagulation had until now been unidentified. In the present study, we identify this component and demonstrate that extracellular vesicles (EVs) present in normal human milk expose coagulant tissue factor (TF). This coagulant activity withstands digestive conditions, mimicking those of breastfed infants, but is sensitive to pasteurization of pooled donor milk, which is routinely used in neonatal intensive care units. In contrast to human milk, bovine milk, the basis of most infant formulas, lacks coagulant activity. Currently, the physiological function of TF-exposing vesicles in human milk is unknown, but we speculate that these vesicles may be protective for infants. Another explanation could be nipple skin damage, which occurs in most breastfeeding women. Milk-derived TF-exposing EVs may seal the wound and thereby reduce bleeding and breast inflammation.

Diurnal variations in tissue factor and tissue factor pathway inhibitor concentrations in relation to on-treatment platelet reactivity: an analysis of patients with acute myocardial infarction

The aim of the study was to evaluate diurnal changes of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) concentrations in relation to on-treatment platelet reactivity. The study group included 51 patients with acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention and dual antiplatelet therapy. TF and TFPI concentrations were assessed using enzyme-linked immunosorbent assay kits. We found a significant increase of TF concentration in clopidogrel-resistant, but not clopidogrel-sensitive, patients at 10.00 a.m. (410.66 pg/mL) in comparison with 6.00 a.m. (250.99 pg/mL), 14.00 p.m. (255.12 pg/mL) and 19.00 p.m. (267.58 pg/mL). Moreover, TF concentration at 10.00 a.m. was 30% higher in clopidogrel-resistant than clopidogrel-sensitive patients (p = .043). We failed to demonstrate diurnal variation in TFPI concentration in clopidogrel-resistant patients. However, TFPI concentration in clopidogrel-sensitive patients was significantly higher at 10.00 a.m. as compared with other sampling points (p < .05). We observed a marked elevation in TF concentration at 10.00 a.m. only in aspirin-resistant patients and a significant increase in TFPI concentration at 10 a.m. only in aspirin-sensitive patients. Our findings suggest the presence of diurnal variations in TF and TFPI concentrations in AMI patients, with the highest thrombotic risk in patients with high on-treatment platelet reactivity in the midmorning.