Elevation of the soluble thrombomodulin levels is associated with inflammation after percutaneous coronary interventions

Circulating Thrombomodulin: Release Mechanisms, Measurements, and Levels in Diseases and Medical Procedures

Thrombomodulin (TM) is a type-I transmembrane protein that is mainly expressed on endothelial cells and plays important roles in many biological processes. Circulating TM of different forms are also present in biofluids, such as blood and urine. Soluble TM (sTM), comprised of several domains of TM, is the major circulating TM which is generated by either enzymatic or chemical cleavage of the intact protein under different conditions. Under normal conditions, sTM is present in low concentrations (<10 ng/mL) in the blood but is elevated in several pathological conditions associated with endothelial dysfunction such as cardiovascular, inflammatory, infection, and metabolic diseases. Therefore, sTM level has been examined for monitoring disease development, such as disseminated intravascular coagulation (DIC), sepsis and multiple organ dysfunction syndrome in patients with novel coronavirus disease 2019 (COVID-19) recently. In addition, microvesicles (MVs) that contain membrane TM (MV-TM) have been found to be released from activated cells which also contribute to levels of circulating TM in certain diseases. Several release mechanisms of sTM and MV-TM have been reported, including enzymatic, chemical, and TM mutation mechanisms. Measurements of sTM and MV-TM have been developed and explored as biomarkers in many diseases. In this review, we summarize all these advances in three categories as follows: (1) release mechanisms of circulating TM, (2) methods for measuring circulating TM in biological samples, and (3) correlation of circulating TM with diseases. Altogether, it provides a whole picture of recent advances on circulating TM in health and disease.

Soluble thrombomodulin and cardiovascular disease risk factors in Japanese children

This study aimed to establish standard reference values for soluble thrombomodulin in healthy prepubertal school-aged children and elucidate the relationship between soluble thrombomodulin levels and obesity, metabolic syndrome-associated indices, and other markers of vascular endothelial damage. The participants in this study were healthy Japanese children aged 9-10 years (315 boys and 267 girls). Blood tests for soluble thrombomodulin, leptin, fibrinogen, and general biochemical markers were performed, and the mean and 10th, 50th, and 90th percentiles for each marker were determined. Participants were divided into two groups based on their waist circumference (≥75 vs. <75 cm), and each parameter was compared between the two groups. Analyses were performed to compare subgroups with different numbers of risk factors for cardiovascular disease (CVD). We found that as CVD risk factors accumulated, the levels of total cholesterol, alanine aminotransferase, uric acid, soluble thrombomodulin, fibrinogen, and leptin were significantly elevated, whereas the level of high-density lipoprotein cholesterol significantly decreased. We determined reference values for soluble thrombomodulin in prepubertal children, and our results suggest that soluble thrombomodulin levels contribute to the latent progress of arteriosclerosis from childhood.

Heart-type fatty acid-binding protein (H-FABP), pentraxin-3 (PTX-3) and thrombomodulin in bovine traumatic pericarditis

The aim of this study was to evaluate the biomarkers of cardiac damage such as heart-type fatty acid-binding protein (H-FABP), pentraxin-3 (PTX-3), and thrombomodulin (TM) for the detection and prognosis of bovine traumatic pericarditis (TP). Spontaneous TP was diagnosed on the basis of history, clinical signs, complete blood count, glutaraldehyde test, ultrasonography, and pericardiocentesis findings. H-FABP, PTX-3 and TM levels in serum were compared between 25 Holstein cows diagnosed with spontaneous TP and 10 healthy control cows using bovine-specific ELISA kits. Serum H-FABP in cattle with TP was significantly (P < 0.05) higher than in the control group and positively correlated with cardiac troponin-I (cTnI), creatine kinase myocardial band (CK-MB), PTX-3 and TM (r = 0.683, 0.342, 0.448 and 0.424, respectively; P < 0.05). The serum levels of PTX-3 (P < 0.05) and TM (P < 0.05) in cattle with TP were significantly higher than in the control group. Cardiac damage biomarkers H-FABP, PTX-3 and TM may be useful in the diagnosis of bovine TP.

Potential biomarker panel for predicting organ dysfunction and acute coagulopathy in a polytrauma porcine model

Traumatic injury remains a major cause of morbidity and mortality worldwide, and patients who survived the initial insult are susceptible to an overwhelming inflammatory dysfunction that will lead to acute coagulopathy of trauma (ACOT) and subsequently multiple organ dysfunction syndrome (MODS). Multiple organ dysfunction syndrome-related scoring systems, although they measure organ dysfunction, present clinical markers, and single-cytokine estimates are unable to predict accurately the events of MODS in the clinical setting to aid risk stratification. In this study, a pig model comprising the lethal triad of trauma was used to determine prognostic patterns of early circulating trauma markers so as to predict the development of MODS and ACOT. We measured early expression of several biomarkers (neutrophil gelatinase-associated protein, high-mobility group box 1, C-reactive protein, tumor necrosis factor-α, heart-type fatty acid binding protein, and D-dimers) and clinical parameters for various organ injuries and abnormalities (creatinine, creatine kinase myocardial band, aspartate aminotransferase, and maximum clot firmness) at later time points. The strength of association between the early expression of several biomarkers to the development of MODS and ACOT in polytraumatized pigs was tested using the Spearman correlation coefficient. These biomarkers were found useful to predict the onset of renal, cardiac, hepatic, and hemostatic abnormalities. The findings show that these biomarkers could help to identify, guide, and streamline damage control surgery and earlier intervention to reverse the detrimental outcomes of MODS and ACOT.

Effect of the anti-oxidant probucol on soluble thrombomodulin (sTM) in hypercholesterolemic rabbits

INTRODUCTION

Thrombomodulin is an integral endothelial cell membrane protein, exists not only on the surface of endothelial cells but also as soluble fragments circulating in plasma. Probucol has anti-oxidant properties as well as cholesterol-lowering effects and may affect soluble thrombomodulin (sTM).

METHODS

Sixteen rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into two groups: (1) high-cholesterol group (n=8): maintained high-cholesterol diet; (2) probucol group (n=8): the same diet plus probucol for 6 weeks. Control group (n=8) was fed with normal diet for 14 weeks. The levels of sTM and oxidized low-density lipoprotein (OX-LDL) were measured using ELISA.

RESULTS

There were atherosclerotic lesions in aortas and intimal thickness significantly increased in high-cholesterol group. Probucol significantly reduced the lesion area (56.4%+/-9.8% vs 82.5%+/-10.5%) and decreased the intimal thickness (44.65+/-7.25 mum vs 72.21+/-8.32) as compared with high-cholesterol group, all P<0.01. Probucol decreased the level of OX-LDL and sTM as compared with high-cholesterol group, all P<0.05.

CONCLUSIONS

Probucol retarded the plaques formation may relate to decrease plasma OX-LDL and sTM concentration, which may improve endothelial function in hypercholesterolemic rabbit.

Vascular lesions and s-thrombomodulin concentrations from auricular arteries of rabbits infused with microbubble contrast agent and exposed to pulsed ultrasound

Arterial injury resulting from the interaction of contrast agent (CA) with ultrasound (US) was studied in rabbit auricular arteries and assessed by histopathologic evaluation and s-thrombomodulin concentrations. Three sites on each artery were exposed (2.8 MHz, 5-min exposure duration, 10-Hz pulse repetition frequency, 1.4-mus pulse duration) using one of three in situ peak rarefactional pressures (0.85, 3.9 or 9.5 MPa). Saline, saline/CA, and saline/US infusion groups (n = 28) did not have histopathologic damage. The saline/CA/US infusion group (n = 10) at exposure conditions below the FDA mechanical index limit of 1.9 did not have histopathologic damage, whereas the saline/CA/US infusion group (n = 9) at exposure conditions above the FDA limit did have damage (5 of 9 arteries). Lesions were characteristic of acute coagulative necrosis. Mean s-thrombomodulin concentrations, a marker for endothelial cell injury, were highest in rabbits exposed to US at 0.85 and 3.9 MPa, suggesting that vascular injury may be physiological and not accompanied by irreversible cellular injury.