Plasma Concentrations Of Thrombomodulin Research Articles

Plasma thrombomodulin as a candidate biomarker for the diagnosis and prognosis of HBV-related acute-on-chronic liver failure.

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a complicated syndrome with high short-term mortality. Effective biomarkers are required for its early diagnosis and prognosis. This study aimed to determine the diagnostic and prognostic value of thrombomodulin (TM) in patients with HBV-ACLF. The expression of TM during disease progression was evaluated through transcriptomics analysis. The plasma TM concentrations of 393 subjects with HBV-ACLF (n=213), acute-on-chronic hepatic dysfunction (ACHD, n=50), liver cirrhosis (LC, n=50) or chronic hepatitis B (CHB, n=50), and normal controls (NC, n=30) from a prospective multicenter cohort, were measured to verify the diagnostic and prognostic significance of plasma TM for HBV-ACLF patients by enzyme-linked immunosorbent assay (ELISA). TM mRNA was highly expressed in the HBV-ACLF group compared with the ACHD group (AUROC=0.710). High expression of TM predicted poor prognosis for HBV-ACLF patients at 28/90 days (AUROCs=0.823/0.788). Functional analysis showed that TM was significantly associated with complement activation and the inflammatory signaling pathway. External validation confirmed its high diagnostic accuracy for HBV-ACLF patients (AUROC=0.796). Plasma TM concentrations were correlated with organ failure, including coagulation and kidney failure. Plasma TM concentrations showed a potential prognostic value for 28-day mortality rates (AUROC=0.702). Risk stratification specifically identified HBV-ACLF patients with a high risk of death as having a plasma TM concentration of ≥8.4 ng/mL. This study reveals that the plasma TM can be a candidate biomarker for early diagnosis and prognosis of HBV-ACLF, and might play a vital role in coagulation and inflammation.

Circulating concentrations of glycocalyx degradation products in preeclampsia.

Background and Objectives: Preeclampsia is a multisystem disorder that affects maternal endothelium. The glycocalyx lines and protects the endothelial surface. In severe systemic diseases, like sepsis, it is shed and glycocalyx degradation products can be detected in increased concentrations in plasma. The aim of this study was to compare circulating concentrations of glycocalyx degradation products in degrees of preeclampsia severity. Study design: In this observational study, we included women from the South African PROVE biobank. Women were divided into normotensive controls, women with preeclampsia without end-organ complications, women with a single end-organ complication and women with multiple end-organ complications. Plasma samples taken at inclusion after diagnosis (preeclampsia cases) or at admission for delivery (normotensive controls) were analyzed with ELISA for syndecan-1, hyaluronic acid and thrombomodulin and compared between groups. Results: Women with preeclampsia (n = 47) had increased plasma concentrations of hyaluronic acid (100.3 ng/ml IQR 54.2–204 vs. 27.0 ng/ml IQR (13.5–66.6), p < 0,001) and thrombomodulin (4.22 ng/ml IQR 3.55–5.17 vs. 3.49 ng/ml IQR 3.01–3.68, p = 0.007) but not syndecan-1 compared with normotensive women (n = 10). There were no differences in plasma concentration in any of these biomarkers in women with preeclampsia with no end-organ complications (n = 10) compared with women with preeclampsia and one end-organ complication (n = 24). Women with preeclampsia with two or more end-organ complications (n = 13) had increased plasma concentrations of thrombomodulin (5.46 ng/ml, IQR 4.85–7.83 vs. 4.66 ng/ml, IQR 3.45–4.88, p = 0.042) compared with women with preeclampsia and no end-organ complications. Conclusion: Thrombomodulin was associated with disease severity and may be valuable for risk-stratifying women with preeclampsia.

Therapeutic and Adverse Effects of Thrombomodulin Alfa to Treat Sepsis-Induced Disseminated Intravascular Coagulation.

In the treatment of disseminated intravascular coagulation (DIC), which is a complication of underlying diseases such as infections and malignant tumors, effective plasma concentrations of thrombomodulin (TM) alfa range from 300 to 900 ng/mL; however, appropriate concentrations when treating sepsis-induced DIC are unknown. Thus, our aim was to determine the relationship between plasma concentrations of TM alfa and its therapeutic effects, and hemorrhagic adverse events. First, we calculated the plasma trough concentrations of TM alfa in septic DIC patients. Next, we divided patients into two groups according to their plasma concentrations into a low- and high-concentration group based on a cut-off value of 600 ng/mL. Fourteen and 35 patients were included in the low- and high-concentration groups, respectively. The Japanese Association for Acute Medicine DIC diagnostic criteria score 4 days after TM alfa administration decreased significantly by 2.06 points from baseline in the high-concentration group compared with 0.71 points in the low-concentration group. The 90-day survival rate was significantly higher in the high-concentration group (85.4%) than in the low-concentration group (49.0%) (hazard ratio, 0.27; 95% confidence interval: 0.09-0.86). In contrast, the incidence of serious hemorrhage was not significantly different between the groups. The recommended plasma concentration of TM alfa in the treatment of septic DIC was determined to be higher than 600 ng/mL, and a dose of 380 U/kg (0.06 mg/kg) was necessary to achieve this concentration.

Thrombomodulin and Endothelial Dysfunction in Sickle Cell Anemia

Thrombomodulin (THBD) is a transmembrane protein that regulates endothelial function by 1) binding thrombin and inhibiting its interaction with fibrinogen, 2) augmenting protein C activation, and 3) down-regulating complement activation by inactivating C3a and C5a (PMID 29866818). Reduced THBD function has been implicated in several vasculopathies (PMID 29866818). Oxidative damage increases cleaved non-functional THBD in circulation and increased circulating non-functional THBD predicts the severity of organ damage in thrombotic microangiopathies (PMID 11190905). Vascular endothelial dysfunction is a hallmark feature of sickle cell disease (SCD) that leads to acute and chronic organ damage and may, in part, be mediated by hemolysis (PMID 28248201). Hemolysis leads to release of cell-free hemoglobin which may lead to vasculopathy through consumption of NO, activation of TLR4 pathways, and direct oxidative damage. We investigated whether decreased THBD activity may be implicated in the pathophysiology of SCD vasculopathy in endothelial cells, transgenic sickle mice, and in a prospective cohort of patients with sickle cell anemia. In vitro: We exposed endothelial cells (EA.hy926, ATTC® CRL-2922TM; Manassas, VA) to incremental doses of cell-free hemoglobin. With higher doses of cell-free hemoglobin we observed reduced surface endothelial cell THBD activity at 6 hours of incubation, assessed by cleavage of chromogenic substrate for activated protein C in the presence of thrombin (Figure 1A). In conjunction with the reduced endothelial THBD activity, there were increased concentrations of cleaved THBD in the supernatant by ELISA (R&amp;D Systems, Minneapolis, MN) (Figure 1B). Transgenic sickle mice: At 6 months of age, transgenic sickle mice (Townes model, Jackson Laboratory; Bar Harbor, Maine) had higher plasma concentrations of cleaved non-functional THBD versus hemoglobin AA mice (Figure 2A). Furthermore, staining of the glomerular microvasculature demonstrated decreased endothelial-bound THBD (Figure 2B). Patients with sickle cell anemia: We evaluated whether plasma concentrations of cleaved non-functional THBD are predictive of acute multiorgan failure syndrome (PMID 8109600) in a cohort of 103 SCD patients recruited into a longitudinal kidney cohort study. Clinical and laboratory variables and plasma samples were obtained at the time of enrolment and the patients were monitored prospectively for acute multiorgan failure syndrome. Hemoglobinuria was defined by urine dipstick positive for blood with &amp;lt; 2 red blood cells/high power field. The median age of this cohort was 35 years (interquartile range, 28 - 44 years), 46% were female, 87% had hemoglobin SS genotype, and 47% were on hydroxyurea at the time of enrolment. In cross-sectional analysis, plasma THBD concentrations were greater in patients with hemoglobinuria, a marker of intravascular hemolysis-derived cell-free hemoglobin in circulation exceeding scavenging capability and filtering through the glomerulus, versus without hemoglobinuria (6.1 ± 0.6 µg/mL vs. 3.6 ± 0.4 µg/mL, P = 0.004) (Figure 3A). With a median follow up of 5.5 years (interquartile range, 1.4 - 5.9 years), 18 (17%) SCD patients had a multiorgan failure event. SCD patients with a multiorgan failure event were older (43 vs. 34 years, P = 0.01) but without significant differences in sex, SCD genotype, or hydroxyurea therapy. After adjusting for age, baseline THBD concentrations predicted a greater risk for multi-organ failure syndrome (log-transformed OR 4.0, 95% CI: 1.2 - 13.3; P = 0.01) (Figure 3B). In conclusion, circulating non-functional THBD, a protein that normally functions to reduce vasculopathy when bound to the endothelium, is increased after endothelial cell exposure to incremental doses of hemoglobin in vitro, in hemoglobin SS vs. AA mice, and in SCD patients with versus without hemoglobinuria. Furthermore, circulating THBD is a biomarker that predicted the risk for multi-organ failure syndrome on longitudinal follow up in SCD patients. Future studies investigating the role of THBD in SCD vasculopathy may help improve our understanding for the catastrophic multiorgan failure syndrome and therapies to augment endothelial cell THBD function may guide future intervention practices. Figure 1 Disclosures Gordeuk: Novartis: Consultancy, Honoraria, Research Funding; Emmaus: Consultancy, Honoraria; Global Blood Therapeutics: Consultancy, Honoraria, Research Funding; Modus Therapeutics: Consultancy, Honoraria; Pfizer: Research Funding; Inctye: Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Ironwood: Research Funding; Imara: Research Funding. Saraf:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding.

Activated protein C ameliorates chronic graft-versus-host disease by PAR1-dependent biased cell signaling on T cells

AbstractSoluble thrombomodulin plasma concentrations are elevated in steroid-resistant graft-versus-host disease (GVHD), implying endothelial hypofunctioning for thrombomodulin-dependent generation of activated protein C’s (APC) anticoagulant, anti-inflammatory, and antiapoptotic functions. Recombinant thrombomodulin or APC administration decreases acute GVHD, manifested by intense inflammation and tissue destruction. Here, we administered recombinant murine wild-type (WT) APC to mice with established chronic GVHD (cGVHD), a less-inflammatory autoimmune-like disease. WT APC normalized bronchiolitis obliterans–induced pulmonary dysfunction. Signaling-selective APC variants (3A-APC [APC with lysine 191-193 replaced with 3 alanines] or 5A-APC [APC with lysine 191-193 replaced with 3 alanines and arginine 229/230 replaced with 2 alanines]) with normal cytoprotective properties, but greatly reduced anticoagulant activity, provided similar results. Mechanistically, WT APC and signaling-selective variants reduced T follicular helper cells, germinal center formation, immunoglobulin, and collagen deposition. WT APC can potentially cleave protease-activated receptor 1 (PAR1) at Arg41 or Arg46, the latter causing anti-inflammatory signaling. cGVHD was reduced in recipients of T cells from WT PAR1 or mutated Gln41-PAR1 donors but not from mutated Gln46-PAR1 donors. These data implicate donor T-cell APC-induced noncanonical cleavage at Arg46-PAR1, which is known to confer cytoprotective and anti-inflammatory activities. Together, these data indicate that APC anticoagulant activity is dispensable, whereas anti-inflammatory signaling and cytoprotective cell signaling by APC are essential. Because a phase 2 ischemic stroke clinical trial did not raise any safety issues for 3A-APC treatment, our studies provide a foundational platform for testing in clinical cGVHD therapy.

Correlation of Circulating Microparticles with Coagulation and Fibrinolysis Is Healthy Individuals

IntroductionMicroparticles (MPs) are small membrane blebs that are released in response to cellular activation or apoptosis from the cell surface by proteolytic cleavage of the cytoskeleton. Previous studies have reported low levels of naturally produced cell-derived microparticle in healthy individuals. This study was conducted to assess whether circulating microparticles induce thrombin generation leading to low grade activation of the coagulation system in healthy individuals.Materials & MethodsFlow cytometry analysis of three phenotypes of Platelet derived (PMP), Endothelial derived (EMP) and TF bearing (TFMP) microparticles was done in in the 20 healthy individuals. Triple gating strategy (i) particle size(<0.5µm) (ii) expression of cell surface markers (PMP, CD42a+; EMP, CD62E+; TF bearing MP(TFMP), CD142+) and (iii) phosphatidylserine(Annexin V+) was used. Plasma concentrations of thrombomodulin (TM), Tissue Factor (TF), Tissue factor pathway inhibitor (TFPI), Protein C (PC), Free Protein S (PS), Thrombin antithrombin (TAT) complexes, soluble fibrin monomer (sFM) was done assess the status of coagulation system. Spearman's rank correlation was done examine the role of cell-derived microparticles as critical effectors of thrombosis.Results: the study group comprised of 75% males of the age group (mean±SD27.3±4.32. Total Microparticles (Annexin V+) enumerated in plasma was 1125±355 (count/µl). 52.8% were TFMP [median (IQR)] [380.3(301.8-710.1) (count/µl)]. Highest number of MP originated from activated platelets [249.1(198.9-404.5) (count/µl)], followed by endothelial cells [140.9(124.9-286.0) (count/µl)]. A statistically significant and inverse correlation of EMP's with TAT complex was observed [12.7(6.8-20.1) ng/ml] (r = -0.46, p = 0.01), PS (93.4±20.6 %) (r = -0.52, p = 0.01) and TM (11.4±4.47 ng/ml) (r = -0.56, p = 0.008). Also, TFMP significantly correlated with TF [3.9(3.0-5.0)] (r = 0.46, p = 0.03) and PC (90.4±17.7) (r=-0.42, p=0.04). No correlation was observed between PMP numbers and coagulation pathway markers.Conclusion: Sub optimal degree of coagulation and natural anticoagulation pathway are occurring in healthy individuals. Microparticles moderately correlated with TF levels. Low EMP's levels correlated with the anticoagulation markers and thrombin generation, suggesting that EMPS may have a role in inhibition of thrombosis. The impact of endothelial vesiculation on basal coagulation should be studied further. DisclosuresNo relevant conflicts of interest to declare.

Clinical application of endothelial injury marker in hypertensive patients.

Endothelial damages are one of the most important causes of persistent hypertensive complications. The aim of our study was to discuss the relationship between the molecular markers of endothelial damage, thrombomodulin, and complications in hypertension. A total 132 cases of hypertensive patients, including 13 patients with damage of target organs, were selected as research subjects. And grouping was based on different levels of blood pressure. The blood pressure and thrombomodulin levels were detected among all cases, and their drinking, smoking, and other medical records were tracked. Higher plasma concentration of thrombomodulin was demonstrated in subjects with hypertensive complications compared with without complications [24.5 (18.1,37.55) vs 12.1 (9.1,22.3)TU/mL, P=.001, respectively]. The optimum thrombomodulin cutoff value was determined to be more than 15.5TU/mL, with a sensitivity of 92.3% and a specificity of 63%. With the increase in blood pressure level, thrombomodulin levels in three groups gradually raised [6.15(5.475,12.75) vs 9.75(7.725,13.35) vs 16.45 (10.125,23.725)TU/mL, P=.007, respectively]. With the increase in blood pressure and the occurrence of complications, thrombomodulin showed an increasing trend, which was caused by an increase in the degree of endothelial injury. So, thrombomodulin may serve as a clinically meaningful marker of the progression of hypertension.

Plasma Thrombomodulin (TM) Concentration in Cats with Cardiomyopathies

Plasma Thrombomodulin (TM) Concentration in Cats with Cardiomyopathies

Epidural Analgesia Prevents Endotoxin-Induced Gut Mucosal Injury in Rabbits

In the present study, we evaluated the effect of epidural analgesia on the alterations of gut barrier function elicited by endotoxin in rabbits. After the placement of an epidural catheter, 28 male rabbits were randomized into either 0.5% lidocaine (group E) or saline (group C) group. The solutions (0.4 mL/kg) were epidurally injected, followed by continuous infusion (0.1 mL . kg(-1) . h(-1)) throughout the study period. Under a continuous infusion of lipopolysaccharide (15 microg . kg(-1) . h(-1)), mean arterial blood pressure, intramucosal pH, and plasma thrombomodulin concentrations were measured. At 4 h, mean arterial blood pressure was lower (P < 0.05), intramucosal pH was higher (P < 0.01), and the progression of hemodilution more profound (P < 0.05) in group E versus group C, whereas plasma thrombomodulin levels were increased to a similar extent between the groups. With less wet-to-dry weight ratio of ileum, histopathological injury scores of gut mucosa were significantly less in group E versus group C (P < 0.01). In a separate series of experiments (n = 10 each group), mucosal permeability in group E was significantly less compared with group C (P < 0.05). Collectively, these studies showed that despite a significant decrease of perfusion pressure and arterial oxygen content, epidural analgesia minimized endotoxin-induced functional and structural injury of gut mucosa possibly through endothelium-independent mechanisms.

High plasma homocysteine concentrations are associated with plasma concentrations of thrombomodulin in patients with type 2 diabetes and link diabetic nephropathy to macroangiopathy

In type 2 diabetic patients with or without nephropathy, we examined relationships between plasma concentrations of total homocysteine (tHcy) and clinical macroangiopathy, as well as endothelial dysfunction indicated by plasma thrombomodulin (TM) concentrations. We studied 103 type 2 diabetic patients including 26 with macroangiopathy (12 patients with coronary artery disease [CAD], 10 with stroke, and 4 with peripheral vascular disease [PVD]). Plasma tHcy was measured by high-performance liquid chromatography. Plasma TM was determined by enzyme immunoassay. As an index of glomerular filtration rate, creatinine clearance (Ccr) also was determined in a 24-hour urine collection. Considering all diabetic patients, plasma tHcy concentrations were significantly higher in those with macroangiopathy than in those without (10.4 ± 3.7 v 8.5 ± 2.8 μmol/L, P = .0077). By univariate and multivariate analyses, plasma tHcy was correlated inversely with Ccr. Plasma tHcy concentrations were significantly higher in the patients with overt albuminuria than in those with normoalbuminuria or microalbuminuria. After exclusion of patients with renal insufficiency (Ccr < 60 mL/min), differences in plasma tHcy concentrations between patients with and without macroangiopathy were abolished. By multivariate analysis, total cholesterol, urinary albumin, Ccr, C-peptide, and tHcy retained significant influence on the plasma TM. Even in patients with normal renal function (Ccr ≥ 80 mL/min), plasma tHcy was correlated positively with plasma TM. In conclusions, diabetic nephropathy is a main determinant of plasma tHcy elevation in type 2 diabetic patients. Since plasma TM is independently associated with plasma tHcy, in diabetic patients with overt nephropathy, elevation of tHcy reflecting reduced clearance is a likely cause of endothelial dysfunction, resulting in the atherosclerosis underlying development of cardiovascular disease.

Increase in Thrombomodulin Concentrations After Pulmonary Thromboendarterectomy in Chronic Thromboembolic Pulmonary Hypertension

The objectives of the study were as follows: (1) to identify differences in endothelial dysfunction and altered hemostasis in patients with chronic thromboembolic pulmonary hypertension (CTEPH) compared with patients with acute pulmonary thromboembolism (APTE) uncomplicated by pulmonary arterial hypertension, by measuring the concentrations of thrombomodulin (TM), a receptor for thrombin and a major anticoagulant proteoglycan on the endothelial membrane, and other plasma factors of coagulation and fibrinolysis; and (2) to examine the effects of thromboendarterectomy on TM levels as a parameter of endothelial cell injury leading to abnormal hemostasis as well as to examine the clinical significance of TM as a marker of endothelial injury. Prospective comparison of concentrations of TM and other plasma parameters among patients with CTEPH or APTE and control subjects. We studied 22 healthy subjects (ie, control subjects), 22 patients who had been clinically stabilized after APTE, and 44 patients with CTEPH. In 21 of the patients with CTEPH, measurements were repeated after they had undergone pulmonary thromboendarterectomy. Plasma concentrations of soluble TM in patients with CTEPH were measured and compared with those in patients with APTE. The mean (+/- SD) TM concentration in the CTEPH group (2.5 +/- 0.7 ng/mL) was significantly lower than that in the control group (4.0 +/- 0.6 ng/mL; p < 0.05). In contrast, the mean plasma TM concentration in the APTE group (4.6 +/- 1.9 ng/mL) was similar to that in the control group. After patients underwent pulmonary thromboendarterectomy, the mean TM concentration increased from 2.0 +/- 0.4 to 2.9 +/- 0.7 ng/mL (p < 0.05). In the CTEPH group, the plasma TM concentration was negatively correlated with mean pulmonary arterial pressure and total pulmonary resistance (p < 0.05). A decreased plasma TM concentration may reflect pulmonary vascular endothelial dysfunction leading to altered anticoagulant and fibrinolytic function in CTEPH, which rarely develops after APTE. Plasma TM measurements may be useful in distinguishing CTEPH with severe pulmonary hypertension from recurrent APTE.

Elevation of von Willebrand factor in plasma in diabetic patients with neuropathic foot ulceration.

The present study examines the relationship between markers of endothelial dysfunction and diabetic neuropathy or consequent neuropathic foot ulceration in patients with Type 2 diabetes mellitus. We studied 65 Type 2 diabetic patients including 25 diabetic patients without neuropathy, 27 with neuropathy but no history of foot ulceration, and 13 with neuropathic ulceration. Plasma concentrations of von Willebrand factor (vWF) and soluble thrombomodulin (TM), measures of endothelial dysfunction, were determined by enzyme immunoassays. We performed various tests quantifying aspects of diabetic neuropathy including vibration perception threshold (VPT; for sensory neuropathy), coefficient of variation of R-R intervals (CVR-R; for cardiac autonomic neuropathy), and cold-induced vasodilation in the great toe for peripheral sympathetic neuropathy. CVR-R and cold-induced vasodilation were significantly diminished in patients with neuropathic foot ulceration compared with patients with neuropathy but no history of foot ulceration. Plasma vWF concentrations were positively correlated with VPT and cold-induced vasodilation test, and were inversely correlated with CVR-R. Multivariate analysis disclosed that VPT and percentage vasodilation were independent factors for plasma vWF. Plasma vWF was significantly elevated in patients with foot ulceration compared with patients without neuropathy or those with neuropathy but not foot ulceration. However, plasma TM concentrations did not differ between the three groups. Diabetic patients with neuropathic foot ulceration had severe impairment of cardiac autonomic and peripheral sympathetic nerves. Elevation of vWF in plasma was associated with neuropathic foot ulceration, linking endothelial dysfunction to foot ulceration.

Physical training decreases plasma thrombomodulin in type I and type II diabetic patients.

Endothelial damage is an early step in the pathogenesis of atherosclerosis and its improvement through physical training can contribute to the known reduction of cardiovascular risk associated with exercise. An increase in some endothelium-dependent haemostatic parameters, considered as markers of endothelial damage, has been observed in diabetic patients. The effect of a three-month physical exercise programme on thrombomodulin, tissue factor pathway inhibitor, plasminogen activator inhibitor, tissue-type plasminogen activator and von-Willebrand factor was evaluated in 14 well-controlled patients with Type I (insulin-dependent) diabetes mellitus and 13 patients with Type II (non-insulin-dependent) diabetes mellitus (HbA1c 6.5 +/- 0.8 and 7.4 +/- 0.8%, respectively). A matched control group was also studied. Thrombomodulin at baseline was higher in both Type I and Type II diabetic patients than in their respective matched control subjects (50.0 +/- 16 vs 31.1 +/- 8.7 microg/l, p < 0.05; 51.0 +/- 10 vs 28.5 +/- 11 microg/l, p <0.05, respectively). After the exercise programme, thrombomodulin plasma concentrations had decreased (p < 0.05) in both groups of patients, with final thrombomodulin values being similar to those observed in their control groups (38.2 +/- 11 microg/l for Type I and 34.6 +/- 12 microg/l for Type II patients). The thrombomodulin decrement correlated with baseline thrombomodulin and VO2max increase in Type I diabetic patients. A decrease in tissue factor pathway inhibitor was also observed in Type II diabetic patients. We conclude that the normalisation of plasma thrombomodulin concentrations in Type I and Type II diabetic patients after physical training might reflect the improvement in endothelial function associated with physical exercise.

Effect of α-lipoic acid on the progression of endothelial cell damage and albuminuria in patients with diabetes mellitus: an exploratory study

Oxidative stress plays a central role in the pathogenesis and progression of late microangiopathic complications (diabetic nephropathy) in diabetes mellitus. Previous studies suggested that treatment of diabetic patients with the antioxidant α-lipoic acid reduce oxidative stress and urinary albumin excretion. In this prospective, open and non-randomized study, the effect of α-lipoic acid on the progression of endothelial cell damage and the course of diabetic nephropathy, as assessed by measurement of plasma thrombomodulin and urinary albumin concentration (UAC), was evaluated in 84 patients with diabetes mellitus over 18 months. Forty-nine patients (34 with Type 1 diabetes, 15 with Type 2 diabetes) had no antioxidant treatment and served as a control group. Thirty-five patients (20 with Type 1 diabetes, 15 with Type 2 diabetes) were treated with 600 mg α-lipoic acid per day. Only patients with an urinary albumin concentration <200 mg/l were included into the study. After 18 months of follow up, the plasma thrombomodulin level increased from 35.9±9.5 to 39.7±9.9 ng/ml ( P<0.05) in the control group. In the α-lipoic acid treated group the plasma thrombomodulin level decreased from 37.5±16.2 to 30.9±14.5 ng/ml ( P<0.01). The UAC increased in patients without α-lipoic acid treatment from 21.2±29.5 to 36.9±60.6 ng/l ( P<0.05), but was unchanged with α-lipoic acid. It is postulated that the significant decrease in plasma thrombomodulin and failure of UAC to increase observed in the α-lipoic acid treated group is due to antioxidative effects of α-lipoic acid, and if so that oxidative stress plays a central role in the pathogenesis of diabetic nephropathy. Furthermore, progression of the disease might be inhibited by antioxidant drugs. A placebo-controlled study is needed.

Relationship between soluble thrombomodulin in plasma and coagulation or fibrinolysis in type 2 diabetes

Serum concentration of soluble thrombomodulin (TM) is thought to be a marker for endothelial damage. Although several studies have reported that serum TM concentrations are increased in patients with diabetes mellitus, there is little information on the physiological function of soluble TM in human plasma. To evaluate the relationship of soluble TM in plasma between coagulation and/or fibrinolysis system in patients with diabetes, we measured plasma soluble TM, protein C activity (a natural anticoagulant induced by thrombin–TM complex), prothrombin F1+2 (a direct marker of thrombin generation), and plasmin–α2-antiplasmin complex (PAP) and D dimer (measures of fibrinolytic activity) in 55 patients with type 2 diabetes mellitus. The plasma concentrations of soluble TM ( P<0.01), protein C activity ( P<0.01), prothrombin F1+2 ( P<0.05), PAP ( P<0.001) and D dimer ( P<0.001) were significantly higher in the diabetic patients than the 48 age-matched control subjects. The plasma concentrations of TM and PAP were obviously increased in patients with diabetic nephropathy. In the diabetic patients, the plasma concentrations of soluble TM were inversely correlated with the protein C activity ( r=−0.43, P<0.005), and were positively correlated with the plasma concentrations of prothrombin F1+2 ( r=0.63, P<0.0001) and the plasma PAP concentrations ( r=0.30, P<0.05). The present study demonstrated that both coagulation and fibrinolysis are enhanced concomitantly in patients with type 2 diabetes mellitus, and that an increase in plasma concentration of soluble TM is associated not only with hypercoagulability but also with enhanced fibrinolysis in diabetic patients.

Peripheral blood mononuclear cells isolated from patients with diabetic nephropathy show increased activation of the oxidative-stress sensitive transcription factor NF-kappaB.

Increased oxidative stress and subsequent activation of the transcription factor NF-kappaB has been linked to the development of late diabetic complications. To determine whether oxidative stress dependent NF-kappaB activation is evident in patients with diabetic nephropathy we used an Electrophoretic Mobility Shift Assay based semiquantitative detection system which enabled us to determine NF-kappaB activation in ex vivo isolated peripheral blood mononuclear cells. We examined 33 patients with diabetes mellitus (Type I and Type II). Patients with diabetic nephropathy showed higher NF-kappaB binding activity in Electrophoretic Mobility Shift Assays and stronger immunohistological staining for activated NF-kappaBp65 than patients without renal complications. NF-kappaB binding activity correlated with the degree of albuminuria (r = 0.316) and with thrombomodulin plasma concentrations (r = 0.33), indicative for albuminuria associated endothelial dysfunction. In a 3 day intervention study in which 600 mg of the antioxidant thioctic acid (alpha-lipoic acid) per day were given to nine patients with diabetic nephropathy oxidative stress in plasma samples was decreased by 48% and NF-kappaB binding activity in ex vivo isolated peripheral blood mononuclear cells by 38%. In conclusion, activation of the transcription factor NF-kappaB in ex vivo isolated peripheral blood mononuclear cells of patients with diabetes mellitus correlates with the degree of diabetic nephropathy. NF-kappaB activation is at least in part dependent on oxidative stress since thioctic acid (alpha-lipoic acid) reduced NF-kappaB binding activity.

Thrombin Generation and Activation of the Thrombomodulin Protein C System in Open Heart Surgery Depend on the Underlying Cardiac Disease

The exposure of blood to foreign surfaces during extracorporeal circulation (ECC) leads to an activation of the coagulation system. In arteriosclerotic patients thrombin activation is increased and plasma fibrinogen is elevated, while protein C levels are reduced. In this study we investigated the influence of different cardiac diseases on ECC-induced thrombin generation and activation of the thrombomodulin-protein C system. Twenty-four patients undergoing either elective coronary artery bypass grafting (CABG) or elective aortic valve replacement (AVR) were included in the study. Blood samples were taken at different time intervals before, during and after ECC, and in the postoperative period. Plasma concentrations of thrombin-antithrombin III-complex (TAT), modified antithrombin (ATM), prothrombin fragment F1+2, free protein S, thrombomodulin, and protein C-antigen were determined by ELISA. Fibrinogen and antithrombin III levels were detected by nephelometry. Both groups were comparable with respect to biometric and ECC-related data. TAT concentrations were elevated in both groups after induction and increased during surgery ( p<0.001). As a marker of thrombin generation levels of F1+2 were higher in the CABG group during cardiopulmonary bypass ( p=0.003). In CABG patients ATM peaks were higher during ECC ( p=0.0024). Significantly higher plasma thrombomodulin concentrations were found in CABG patients after induction ( p<0.001), while protein S concentrations were higher in the AVR group ( p=0.002). Protein C levels and antithrombin III concentrations did not differ between the groups. Patients undergoing CABG were found to have lower protein S levels and increased plasma thrombomodulin concentrations as markers of endothelial damage. In these patients contact activation and as a consequence thrombin generation takes place at a higher level, indicating a hypercoagulable state. Thromboembolic events in the perioperative period may be caused by different hemostatic changes in CABG patients.

RETRACTED: Endothelial-Related Coagulation in Pediatric Surgery

The endothelium plays a pivotal role in the regulation of anticoagulant and procoagulant pathways and imbalance can produce disturbances in coagulation. Serine protease inhibitors are also important controllers of the coagulation system. Aprotinin can reduce postoperative bleeding, although the mechanism of action is not clearly defined. This article focuses on a study in children with congenital heart disease scheduled for cardiac operations to determine the influence of aprotinin on plasmatic or endothelial-related natural inhibitors. Thirty children were randomly allocated either to an aprotinin-treated group or to a control group. Levels of thrombomodulin, protein C, free protein S, and thrombin/antithrombin complex were measured before, during, and after cardiopulmonary bypass until the first postoperative day. Levels of antithrombin III, protein C and protein S, and fibrinogen, platelet count, and activated partial thromboplastin time were without differences between the two groups. Thrombin/antithrombin plasma concentrations increased significantly during cardiopulmonary bypass, without showing any differences between aprotinin-treated and nontreated children. Thrombomodulin plasma concentrations during cardiopulmonary bypass and until 5 hours after cardiopulmonary bypass were significantly lower in the aprotinin-treated children than in the control group. By the first postoperative day, the levels in the aprotinin-treated patients had returned to baseline. The results suggest a direct or indirect effect of aprotinin on endothelial cell thrombomodulin expression and release in a soluble form into the circulation. Whether the lower plasma concentrations with aprotinin are related to suppression of proinflammatory mediators and preservation of endothelial cell function or whether aprotinin has a direct action on thrombomodulin expression by the endothelium can only be speculated.

Thrombomodulin serum levels in ventilated preterm babies with respiratory distress syndrome.

A soluble form of thrombomodulin (TM), an anticoagulant proteoglycan of the endothelial cell membrane, considered a marker of vascular endothelial damage, was measured in plasma of preterm infants with respiratory distress syndrome (RDS). In these patients, lung immaturity leads to endothelial leak of plasma proteins and to surfactant inhibition. In 18 babies with RDS, plasma TM concentration was significantly elevated compared with values of a matched group of babies without pulmonary disease (276.1 ng/ml vs 141.3 ng/ml) (P < 0.05). Furthermore, TM levels of mechanical ventilated babies (IPPV) with severe RDS were higher than those of babies with moderate RDS and treated with nasal CPAP (340.9 ng/ml vs 174.2 ng/ml) (P < 0.05). These data show that TM can be used as marker of pulmonary endothelial damage in preterm babies treated with mechanical ventilation for RDS and suggest early intervention with exogenous surfactant to limit alveolar protein leakage and surfactant inactivation.

Plasma thrombomodulin level in very low birthweight infants at birth.

Plasma soluble thrombomodulin level reflects endothelial damage. The plasma thrombomodulin level at birth is increased in asphyxiated full-term infants. There is no report of plasma thrombomodulin level in premature infants. To determine the thrombomodulin level in premature infants and whether it might reflect endothelial damage, we examined the plasma thrombomodulin level in very low birthweight (VLBW) infants at birth. Forty-five VLBW infants, of whom 14 had perinatal asphyxia complications, were recruited. As a control, 50 full-term infants without complications were also studied. Plasma thrombomodulin concentration, pH, base deficit, serum creatinine and D-dimer concentration, platelet count and fibrinogen concentration were measured within 1 hour after birth. There were significant differences in plasma pH, creatinine concentration, platelet count, antithrombin III activity and D-dimer concentration between VLBW infants and full-term infants. Plasma thrombomodulin concentration (39.0 (16.6-93.7) vs 27.0 (16.6-39.1) microg/L, p < 0.0001) and plasma thrombomodulin-to-serum creatinine ratio (0.82 (0.19-2.65) vs 0.47 (0.24-0.70) microg/micromol, p < 0.0001) were significantly higher in VLBW infants than those in full-term infants. By univariate analyses for all neonates, there were significant relations between plasma thrombomodulin concentration and gestational age, birthweight, plasma pH, creatinine concentration, platelet count and antithrombin III activity. A stepwise multiple linear regression model using the above variables as dependent factors showed only birthweight contributed significantly to plasma thrombomodulin concentration (plasma thrombomodulin concentration (microg/l) = 45.677-0.006 (birthweight; g), r2 = 0.323, p < 0.0001, n = 94). Plasma thrombomodulin concentration and plasma thrombomodulin-to -serum creatinine ratio in VLBW infants with asphyxia were higher than in those without asphyxia, but not significantly different (43.2 +/- 17.7 vs 38.3 +/- 8.5 microg/l and 0.92 +/- 0.60 vs 0.83 +/- 0.37 microg/micromol). Plasma thrombomodulin level in VLBW infants shows a high value at birth, and we consider the main factor responsible for this elevation may be endothelial damage or low clearance rate of thrombomodulin, which may be related to early gestational age.