Thrombin generation as a predictor of thromboembolic events in multiple myeloma patients

Thrombin Generation Markers as Predictors of Cancer-Associated Venous Thromboembolism: A Systematic Review

Venous thromboembolism (VTE) is a main contributor to morbidity and mortality in cancer patients. Biomarkers with the potential to predict cancer-associated VTE are continually sought. Of these, markers of thrombin generation present a likely option. The present systematic review examines the ability of three widely used biomarkers of thrombin generation: prothrombin fragment 1.2 (F1.2), thrombin-antithrombin complex (TAT), and ex vivo thrombin generation, to predict VTE in both solid and hematologic adult cancer patients. Relevant studies were identified in the PubMed and Embase databases, and the review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Each study was evaluated using the quality assessment tool from the National Heart, Lung, and Blood Institute. The review protocol was published on PROSPERO with identifier CRD42022362339. In total, 24 papers were included in the review: 11 reporting data on F1.2, 9 on TAT, and 12 on ex vivo thrombin generation. The quality ratings of the included studies varied from good (n = 13), fair (n = 8), to poor (n = 3) with a high heterogenicity. However, F1.2, TAT complex, and ex vivo thrombin generation were all found to be associated with the development of VTE. This association was most pronounced for F1.2. Furthermore, the determination of F1.2 was able to improve the precision of several established risk assessment scores. In conclusion, markers of thrombin generation were found to be elevated in cancer patients with VTE, and particularly, F1.2 was found to be a promising predictor of cancer-associated VTE.

Patients with multiple myeloma and monoclonal gammopathy of undetermined significance have variably increased thrombin generation and different sensitivity to the anticoagulant effect of activated protein C

BACKGROUND

Patients with multiple myeloma (MM) are at high risk of thrombosis especially when receiving immunomodulatory therapy. Thrombotic risk in patients with monoclonal gammopathy of undetermined significance (MGUS) may also be increased. Although activated protein C (APC) resistance has been linked to an increased risk of thrombosis in MM, little is known about how APC influences thrombotic risk in MGUS. We compared thrombin generation (TG) in MM and MGUS patients to that of healthy controls (HCs) and investigated the exogenous effect of APC on TG in these groups.

METHODS

Hemostasis tests including factor VIII (FVIII) and von Willebrand factor (vWF) levels were measured in platelet-poor plasma in 14 untreated MM patients, 34 MGUS patients, and 30 age and sex-matched HCs. TG assay was performed with or without the addition of APC.

RESULTS

Peak thrombin and velocity index were significantly higher in MM and MGUS patients compared to HCs, while MM patients also had elevated endogenous thrombin potential (ETP). In MGUS cases, ETP and peak thrombin values significantly correlated with FVIII and vWF levels. In the presence of APC, peak thrombin and ETP were reduced in MGUS and control plasmas whereas lagtime and time to peak were significantly prolonged. In contrast, adding APC to MM plasma had no effect on any TG parameters.

CONCLUSIONS

Hypercoagulability was observed in MM and even in MGUS cases with very low monoclonal protein concentration. In MM patients, APC had no effect on TG, but it attenuated TG in MGUS patients.

Enhanced thrombin generation detected with ST-Genesia analyzer in patients with newly diagnosed multiple myeloma

The issue of how to identify newly diagnosed multiple myeloma (NDMM) patients requiring thromboprophylaxis remains unsolved. Several changes in thrombin generation (TG)-derived parameters have been described in multiple myeloma (MM) patients recently. Assessment of prothrombotic risk with a fully automated TG analyzer could reduce interlaboratory variability. Our objective was to determine whether ST-Genesia^® could reveal a hypercoagulable state in NDMM compared to healthy controls. We conducted a multicenter observational study of NDMM requiring initial treatment to compare TG parameters obtained with ST-Genesia^® analyzer and ST-ThromboScreen^® reagent with a control group. Clinical data were obtained from medical records and blood samples were collected before initial anti-myeloma therapy. A thrombophilia panel was performed in all patients. Compared to age- and sex-matched controls (n = 83), NDMM patients (n = 83) had significantly higher peak height, higher velocity index, shorter time-to-peak and lower percentage of endogenous thrombin potential (ETP) inhibition after adding thrombomodulin (TM) (ETP%inh). NDMM on prophylactic low molecular weight heparin (LMWH) showed reduced both peak height and velocity index compared to NDMM who had not yet started VTE prophylaxis, similar to that of controls. Moreover, partial correction of ETP%inh was observed in MM patients on LMWH. The presence of a thrombophilia did not modify the TG phenotype. Untreated NDMM patients showed an enhanced TG, regardless of their thrombophilia status. They generate a higher peak of thrombin, take less time to produce it, and exhibit resistance to TM inhibition. Our findings suggest that standard prophylactic dose of LMWH may reduce TG at levels of healthy controls.

Evaluation of Haemostasis in Dogs Affected by Resectable Malignancy

Dogs with neoplasm are at risk of thrombosis, yet there is no information on the haemostatic alterations that may result from the surgeries performed to remove neoplastic masses. The aim of this study was to observe the characteristics of haemostasis in dogs undergoing surgery to remove a malignancy by means of rotational thromboelastometry and thrombin generation. Haemostasis was assessed immediately before surgery (T0), 24 h after surgery (T1), and two weeks after surgery (T2). Statistically significant differences were found between the thromboelastometric parameters at T0 vs. T1, with increases observed in MCF, the α angle, and G parameters in the ex-TEM and in-TEM profiles. In the thromboelastometric analysis performed after surgery differences were identified between T1 and T2, with a decrease observed in parameters such as CFT, MCF, the α angle, and G. Between T0 and T2, only a significant decrease in CT was detected in the fib-TEM profile. No differences were found in the comparison among the results obtained via thrombin generation. In dogs with resectable malignancies, the surgeries performed to remove cancer affected coagulation, causing a tendency towards hypercoagulability. The interference with coagulation was transient, and 2 weeks after surgery, the thromboelatometric results returned to those obtained before surgery (T0).

Thromboprophylaxis in multiple myeloma

Venous thromboembolism (VTE) in multiple myeloma (MM) can be secondary to patient-, disease-, and/or treatment-related factors. The development of VTE may result in significant morbidity with the highest risk during the first year after diagnosis. This clinical review provides an evidence-based summary to guide practicing oncologists in the use of anticoagulation to prevent VTE in multiple myeloma and includes anticoagulation efficacy and adverse effect profile. We highlight the pathophysiology of VTE in MM, the use of various risk prediction tools, and the current recommendations for the use of different anticoagulants in prophylaxis of VTE.

The role of VWF/FVIII in thrombosis and cancer progression in multiple myeloma and other hematological malignancies

Cancer associated thrombosis (CAT) is associated with significant morbidity and mortality, highlighting an unmet clinical need to improve understanding of the pathophysiology of CAT. Multiple myeloma (MM) is associated with one of the highest rates of thrombosis despite widespread use of thromboprophylactic agents. The pathophysiology of thrombosis in MM is multifactorial and patients with MM appear to display a hypercoagulable phenotype with potential contributory factors including raised von Willebrand factor (VWF) levels, activated protein C resistance, impaired fibrinolysis, and abnormal thrombin generation. In addition, the toxic effect of anti-myeloma therapies on the endothelium and contribution to thrombosis has been widely described. Elevated VWF/factor VIII (FVIII) plasma levels have been reported in heterogeneous cohorts of patients with MM and other hematological malignancies. In specific studies, high plasma VWF levels have been shown to associate with VTE risk and reduced overall survival. While the mechanisms underpinning this remain unclear, dysregulation of the VWF and A Disintegrin And Metalloprotease Thrombospondin type 1, motif 13 (ADAMTS-13) axis is evident in certain solid organ malignancies and correlates with advanced disease and thrombosis. Furthermore, thrombotic microangiopathic conditions arising from deficiencies in ADAMTS-13 and thus an accumulation of prothrombotic VWF multimers have been reported in patients with MM, particularly in association with specific myeloma therapies. This review will discuss current evidence on the pathophysiological mechanisms underpinning thrombosis in MM and in particular summarize the role of VWF/FVIII in hematological malignancies with a focus on thrombotic risk and emerging evidence for contribution to disease progression.

Analysis of Coagulation Abnormality in Patients with Multiple Myeloma and Its Clinical Significance

Objective

To analyze the abnormal changes of coagulation indexes in patients with multiple myeloma (MM) and their clinical significance on prognosis.

Methods

Among 80 patients with MM, there were 24 patients of light chain type, 36 patients of IgG type, and 20 patients of IgA type. In the same period, 30 healthy people were in the control group. The laboratory indexes such as plasma prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), thromboplastin time (TT), D-dimer (D-D), and platelet (PLT) were detected and compared. The prognosis of MM patients was followed up, and the effects of various coagulation indexes on the prognosis of MM were analyzed by single-factor and multifactor analyses.

Results

The PT and APTT of IgG and IgA groups were longer than those of the control group and the light chain group (P < 0.05), but there was no significant difference between the IgG group and the IgA group, the control group, and the light chain group. There was no significant difference in FIB values among the four groups (P > 0.05). The D-D content in the light chain group was higher than that in the control group, the IgG group, and the IgA group (P < 0.05). During the follow-up period, of 80 MM patients, 61 patients survived and 19 patients died. Univariate analysis showed that APTT, PT, and D-D were the factors affecting the prognosis of MM patients, and the differences were statistically significant (P < 0.05). Multivariate analysis showed that PT was an independent factor affecting the prognosis of MM patients (P < 0.05). Discussion. Patients with MM have clotting abnormalities. Patients with IgA and IgG type MM have a longer clotting time than patients with other types of MM, and patients with light-chain type MM have higher D-D content and are more prone to thrombosis. PT is an independent factor affecting the prognosis of MM patients, and analysis of coagulation abnormalities is important for evaluating the prognosis of patients.

Patients With Multiple Myeloma Have a Disbalanced Whole Blood Thrombin Generation Profile

Background

Multiple myeloma (MM) is associated with a high prevalence of bleeding and an increased risk of thrombo-embolism. MM patients have reduced platelet- and red blood cell (RBC) numbers in blood, which may indicate that the paradoxical hemostasis profile is a consequence of a disturbed platelet and RBC homeostasis.

Objectives

To get better insight in the disbalanced hemostasis of MM patients.

Methods

We conducted a case-control study on the whole blood (WB) coagulation profiles of 21 MM patients and 21 controls. We measured thrombin generation (TG) in WB and platelet poor plasma (PPP) of MM patients and controls.

Results

In WB-TG, we observed that the median time to the thrombin Peak was 52% longer in MM patients than in controls, while the median endogenous thrombin potential until the Peak (ETPp) was 39% higher in MM-patients than in controls. In line with these findings, the levels of platelets, RBCs, white blood cells and agonist induced platelet activation were decreased in MM patients compared to controls. The plasma TG experiments showed no differences between MM-patients and controls.

Conclusion

Patients with MM have a disturbed blood cell metabolism and a disbalanced WB-TG profile. This disbalance may explain the paradoxically high prevalence of bleeding symptoms in MM patients vs. an increased thrombosis risk. There was no disturbance observed in plasma TG, indicating that blood cells are the major determinants for the disbalanced hemostasis in MM patients.

Perioperative coagulation profile in major liver resection for cancer: a prospective observational study

Hepatectomy induced coagulation disturbances have been well studied over the past decade. Cumulative evidence supports the superiority of global coagulation analysis compared to conventional coagulation tests (i.e. PT or aPTT) for clinical decision making. Cancer, however, represents an acquired prothrombotic state and liver resection for cancer deserves a more thorough investigation. This prospective observational study was conducted to assess the perioperative coagulation status of patients undergoing major hepatectomies for primary or metastatic hepatic malignancy. Patients were followed up to the 10th postoperative day by serial measurements of conventional coagulation tests, plasma levels of coagulation factors and thrombin generation assay parameters. An abnormal coagulation profile was detected at presentation and included elevated FVIII levels, decreased levels of antithrombin and lag time prolongation in thrombin generation. Serial hematological data demonstrated increased vWF, FVIII, D-dimer, fibrinogen and decreased levels of natural anticoagulant proteins in the early postoperative period predisposing to a hypercoagulable state. The ratio of the anticoagulant protein C to the procoagulant FVIII was low at baseline and further declined postoperatively, indicating a prothrombotic state. Though no bleeding complications were reported, one patient experienced pulmonary embolism while under thromboprophylaxis. Overall, patients with hepatic carcinoma presenting for elective major hepatectomy may have baseline malignancy associated coagulation disturbances, aggravating the hypercoagulable state documented in the early postoperative period.

Dual-target synergistic antithrombotic mechanism of a Dabigatran etexilate analogue (HY023016)

Thrombin has long been considered a desirable antithrombotic target, but anti-thrombin therapy without anti-platelet therapy has never achieved the ideal effect. HY023016, derived from dabigatran etexilate, exhibited a potent antithrombotic efficacy. In the present study, mechanisms underlying this effect were explored. HY023016 strongly decreased the binding of thrombin to recombinant GPIbα N-terminal sequence which was confirmed by surface plasmon resonance. Flow cytometry revealed that HY023016 selectively decreased the binding of antibody to GPIbα and inhibited the washed human platelet aggregation induced by thrombin. Fluorescence experiment showed that HY023016 remarkably inhibited exosite II by a loss of affinity for the γ'-peptide of fibrinogen. Using intravital microscopy, we observed and recorded the dynamic process of thrombus formation and found that HY023016 effectively prevented thrombus formation in rat arteriovenous shunt thrombosis model. On the basis of these findings, we propose that HY023016 provides a novel insight into the antithrombotic mechanism, which exerts synergistic anticoagulant and antiplatelet effects through thrombin and GPIbα.

DNase 1 Protects From Increased Thrombin Generation and Venous Thrombosis During Aging: Cross-Sectional Study in Mice and Humans

Background Human aging is associated with increased risk of thrombosis, but the mechanisms are poorly defined. We hypothesized that aging induces peroxide-dependent release of neutrophil extracellular traps that contribute to thrombin generation and thrombosis. Methods and Results We studied C57BL6J mice and littermates of glutathione peroxidase-1 transgenic and wild-type mice at young (4 month) and old (20 month) ages and a healthy cohort of young (18-39 years) or middle-aged/older (50-72 years) humans. In plasma, we measured thrombin generation potential and components of neutrophil extracellular traps (cell-free DNA and citrullinated histone). Aged wild-type mice displayed a significant increase in thrombin generation that was decreased in aged glutathione peroxidase-1 transgenic mice. Both aged wild-type and aged glutathione peroxidase-1 transgenic mice demonstrated similar elevation of plasma cell-free DNA compared with young mice. In contrast, plasma levels of citrullinated histone were not altered with age or genotype. Release of neutrophil extracellular traps from neutrophils in vitro was also similar between young and aged wild-type or glutathione peroxidase-1 transgenic mice. Treatment of plasma or mice with DNase 1 decreased age-associated increases in thrombin generation, and DNase 1 treatment blocked the development of experimental venous thrombi in aged C57BL6J mice. Similarly, thrombin generation potential and plasma cell-free DNA, but not citrullinated histone, were higher in middle-aged/older humans, and treatment of plasma with DNase 1 reversed the increase in thrombin generation. Conclusions We conclude that DNase 1 limits thrombin generation and protects from venous thrombosis during aging, likely by hydrolyzing cell-free DNA.

Global coagulation assays in hypercoagulable states

Thrombosis is one of the major global causes of morbidity and mortality, and predicting the risk of thrombotic and cardiovascular complications remains one of the key challenges in modern medicine. Conventional coagulation testing does not provide sufficient information, primarily because they measure the time to start of blood clotting and do not evaluate total thrombin generation. Possible adjunctive tools that may be helpful are global coagulation assays, which includes the assessment of the final products of the coagulation cascade, namely thrombin and fibrin. Whilst these assays have been more widely investigated in bleeding states, their role in thrombotic disorders is less established. We have previously investigated the use of assays such as thromboelastography, calibrated automated thrombogram and overall haemostatic potential assay in several hypercoagulable states including cardiovascular disease, haematological disorders and influence of hormone status as well as healthy controls. We provide a review of the use and limitations of global coagulation assays in healthy controls as well as hypercoagulable conditions.

Hemostatic Biomarkers and Cancer Prognosis: Where Do We Stand?

Cancer patients are characterized by hypercoagulable state and an increased rate of thrombotic events, the most common being venous thromboembolism. Several hemostatic pathways that are significantly implicated in mechanisms of thromboembolic disease are also involved in growth, invasion, and metastatic spread of malignant cells as well in tumor-induced neo-angiogenesis. This close connection between cancer and the hemostatic system has prompted numerous studies on the role of alterations in the level plasma biomarkers of the different compartments of hemostasis in predicting cancer prognosis. In this review, we collect the results of several exemplificative studies that have evaluated clotting activation biomarkers in relation to different cancer outcomes with a final emphasis on current research and forthcoming directions in this field.

Femtomolar Detection of Thrombin in Serum and Cerebrospinal Fluid via Direct Electrocatalysis of Oxygen Reduction by the Covalent G4-Hemin-Aptamer Complex

Thrombin, a serine protease playing a central role in the coagulation cascade reactions and a potent neurotoxin produced by injured brain endothelial cells, is a recognized cardiac biomarker and a critical biomarker for Alzheimer's disease development. Both in vivo and in vitro, its low physiological concentrations and nonspecific binding of other components of physiological fluids complicate electroanalysis of thrombin. Here, femtomolar levels of thrombin in serum and an artificial cerebrospinal fluid (CSF) were detected by the indicator-free electrochemical methodology exploiting the O₂ reduction reaction directly, with no electron transfer mediators, electrocatalyzed by the covalent G4-hemin DNAzyme complex naturally self-assembling upon thrombin binding to the hemin-modified 29-mer DNA aptamer sequence tethered to gold via an alkanethiol linker. Coadsorbed PEG inhibited nonspecific protein binding and allowed the sought signal resolution. The proposed assay exploiting the "oxidase" activity of G4-hemin DNAzyme does not require any coreactants necessary for the traditional peroxidase activity-based assays with this DNAzyme, such as H₂O₂ and redox mediators, or solution deaeration and allows fast, overall 30 min analysis of thrombin in aerated buffer, CSF, and 1% human serum solutions. This pioneer approach exploiting the oxidase activity G4-hemin DNAzyme is simple, sensitive, and selective and represents a new tool for ultrasensitive electrocatalytic assays based on simple and efficient O₂-dependent DNAzyme labels.

Prothrombotic abnormalities in patients with multiple myeloma and monoclonal gammopathy of undetermined significance

BACKGROUND

Multiple myeloma (MM) and its precursor condition, monoclonal gammopathy of undetermined significance (MGUS) have an increased risk of thrombotic events, especially during anti-myeloma treatment. Many different underlying causes for this hypercoagulability have been suggested, but current techniques to identify abnormalities in these patients are sparse and inefficient. The aim of this study was to assess the hypercoagulability in MGUS and MM patients through various coagulation analyses and identify changes in the MM patients throughout their treatment regimen.

MATERIALS AND METHODS

Platelet-free plasma from 38 MM patients, 19 MGUS patients and 34 healthy controls were tested for hypercoagulability using calibrated automated thrombogram, a procoagulant phospholipid assay, a microvesicle-associated (MV) tissue factor (TF) assay, and a cell-free deoxyribonucleic acid (cf-DNA) assay as a surrogate measurement for neutrophil extracellular traps (NETs).

RESULTS

MGUS and MM patients both had elevated thrombin generation and procoagulant phospholipid activity in comparison to the control subjects. MM, and partly MGUS, showed increased MV-TF activity, however, only MM had increased levels of the cf-DNA.

CONCLUSIONS

Here we demonstrated that hypercoagulability was present in patients with MGUS and MM through increased thrombin generation, possibly due to higher TF and procoagulant phospholipids (PPL) activity. This may be associated to MVs and, for MM patients, be attributed to procoagulant NETs activity; however, this remains to be determined.

The potential role of emicizumab prophylaxis in severe von Willebrand disease

BACKGROUND

Severe von Willebrand disease (VWD) may be associated with chronic joint damage and may require prophylactic therapy. Emicizumab is a humanized bispecific antibody, which mimics the function of coagulation factor VIII (FVIII), and it has been approved for prophylaxis in hemophilia A.

METHODS

This is the first study assessing the potential future role of emicizumab as an alternative prophylactic treatment in patients with severe VWD, based upon a thrombin generation (TG) ex vivo analysis. We report 51 weeks of successful off label emicizumab prophylaxis in a child with severe VWD and recurrent hemarthroses and progressive arthropathy despite adherence to previous prophylaxis with replacement therapy.

RESULTS AND CONCLUSIONS

Our work demonstrated that ex vivo spiking with emicizumab increased TG in plasma from patients with type 3 VWD. Similar TG results were observed in our treated patient, whose therapy was well tolerated without any adverse events. Both in vitro and ex vivo TG data support sufficient hemostasis without exceeding the range seen in healthy volunteers. Further collaborative studies on the efficacy and safety of emicizumab prophylaxis in severe VWD is warranted.

Multiple Myeloma and Thrombosis: Prophylaxis and Risk Prediction Tools

Thromboembolism in multiple myeloma (MM) patients remains a common complication that renders the optimization of our thromboprophylaxis practice necessary. This review aims to make clear the need for the development of more accurate risk assessment tools and means of thrombosis prevention. Current clinical practice is guided by available guidelines published by the IMWG in 2014, but the extent to which these are implemented is unclear. Recently, several groups developed clinical scores for thrombosis risk in MM in an attempt to improve risk stratification, but these have not been validated or used in clinical practice so far. Research in this field is increasingly focusing on understanding the unique coagulation profile of the MM patient, and data on potential biomarkers that accurately reflect hypercoagulability is emerging. Finally, promising evidence on the effectiveness of direct oral anticoagulants (DOACs) in the context of thrombosis prevention in MM patients is increasingly becoming available. The critical appraisal of the above research areas will establish the necessity of combining disease-specific clinical risk factors with coagulation biomarkers to allow more effective risk stratification that will eventually lead to the reduction of this significant complication. Results from ongoing clinical trials on the role of DOACs are much anticipated.

The hypercoagulable state in multiple myeloma: The contribution of thrombin generation test

BACKGROUND

Multiple myeloma is a hematologic malignancy which confers a high venous thromboembolic risk. This risk is linked to patient-related factors, disease-specific mechanisms, and antimyeloma therapy, especially immunomodulatory drugs. Some studies have suggested that the thrombin generation assay may be a predictive marker of thrombosis. This study aimed to assess the hypercoagulable state in patients with multiple myeloma at diagnosis and after myeloma therapy.

METHODS

Thirty-one patients with multiple myeloma were included in a prospective study and were compared with 31 matched controls with age and gender. Thrombin generation assay was performed in patients at diagnosis prior to treatment initiation and at the end of myeloma therapy, and in controls. Parameters of lag time, peak thrombin concentration, time to peak, endogenous thrombin potential, and velocity index were analyzed.

RESULTS

Median age of patients at diagnosis was 58 years (11 men and 20 women). Twenty-three patients (74%) were classified as high vascular risk and received thromboprophylaxis. No thromboembolic events have been reported during follow-up, except a symptomatic pulmonary embolism in one patient which occurred at diagnosis. At baseline, patients with myeloma had significantly elevated velocity index as compared to controls (178 vs 128 nmol/L/min; P = .013). High-risk patients showed an elevation of plasma thrombin generation as compared to low-risk patients (endogenous thrombin potential = 1244 vs 1052 nmol/L/min; P = .043). Myeloma therapy did not significantly change the thrombin generation parameters.

CONCLUSION

Thrombin generation appears to be higher in patients with myeloma compared with controls, especially in high-risk patients, and does not change significantly after treatment completion.

Thrombin Generation and Cancer: Contributors and Consequences

The high occurrence of cancer-associated thrombosis is associated with elevated thrombin generation. Tumour cells increase the potential for thrombin generation both directly, through the expression and release of procoagulant factors, and indirectly, through signals that activate other cell types (including platelets, leukocytes and erythrocytes). Furthermore, cancer treatments can worsen these effects. Coagulation factors, including tissue factor, and inhibitors of coagulation are altered and extracellular vesicles (EVs), which can promote and support thrombin generation, are released by tumour and other cells. Some phosphatidylserine-expressing platelet subsets and platelet-derived EVs provide the surface required for the assembly of coagulation factors essential for thrombin generation in vivo. This review will explore the causes of increased thrombin production in cancer, and the availability and utility of tests and biomarkers. Increased thrombin production not only increases blood coagulation, but also promotes tumour growth and metastasis and as a consequence, thrombin and its contributors present opportunities for treatment of cancer-associated thrombosis and cancer itself.

Extracellular vesicle-associated procoagulant phospholipid and tissue factor activity in multiple myeloma

Multiple myeloma (MM) patients have increased risk of developing venous thromboembolism, but the underlying mechanisms and the effect on the coagulation system of the disease and the current cancer therapies are not known. It is possible that cancer-associated extracellular vesicles (EV), carrying tissue factor (TF) and procoagulant phospholipids (PPL) may play a role in thrombogenesis. The aim of this study was to perform an in-depth analysis of procoagulant activity of small and large EVs isolated from 20 MM patients at diagnosis and after receiving first-line treatment compared with 20 healthy control subjects. Differential ultracentrifugation at 20,000 × g and 100,000 × g were used to isolate EVs for quantitative and phenotypical analysis through nanoparticle tracking analysis, Western blotting and transmission electron microscopy. The isolated EVs were analyzed for procoagulant activity using the calibrated automated thrombogram technique, a factor Xa-based activity assay, and the STA Procoag-PPL assay. In general, MM patients contained more EVs, and immunoelectron microscopy confirmed the presence of CD9- and CD38-positive EVs. EVs in the 20,000 × g pellets from MM patients exerted procoagulant activity visualized by increased thrombin generation and both TF and PPL activity. This effect diminished during treatment, with the most prominent effect observed in the high-dose chemotherapy eligible patients after induction therapy with bortezomib, cyclophosphamide, and dexamethasone. In conclusion, the EVs in patients with MM carrying TF and PPL are thus capable of exerting procoagulant activity.

Thrombin generation in newly diagnosed multiple myeloma during the first three cycles of treatment: An observational cohort study

BACKGROUND

Multiple myeloma (MM) is associated with a high risk of thrombosis, particularly during the first months of treatment including immunomodulatory drugs (IMiDs). There is no consensus on prevention of thromboembolic risk in patients with de novo MM, and identification of patients requiring anticoagulant thromboprophylaxis remains challenging. Evaluating coagulability by an in vitro thrombin generation (TG) test might be a way of identifying such patients.

OBJECTIVE

To determine whether TG assessment could reveal an increase in coagulability during the first three chemotherapy cycles.

METHODS

This prospective and longitudinal observational study included patients newly diagnosed with MM. TG was determined in platelet-rich and platelet-poor plasma using calibrated automated thrombography with a low tissue factor (TF) concentration.

RESULTS

Seventy-one patients were enrolled, allowing TG analysis during 213 chemotherapy cycles. TG remained unchanged throughout follow-up irrespective of treatment regimen, but values determined before cycles 2 and 3 were significantly higher in patients receiving iMiDs-containing regimens. No association was found between TG and its changes and thrombosis occurrence during follow-up: venous thrombosis in eight patients; no cardiovascular event. A significantly (87%) lower risk of venous thrombosis was observed in patients receiving prophylaxis with a low-molecular-weight heparin (LMWH; OR: 0.13 (95% CI: 0.02-0.76). Neither bortezomib- nor dexamethasone-containing regimens were associated with thrombotic risk. Changes in TG, as studied, were not associated with thrombotic events.

CONCLUSIONS

The only factor associated with a reduction in early thrombotic risk was prophylaxis with LMWH. The issue of how to identify patients requiring prophylactic anticoagulation remains unresolved.

Hemostatic biomarkers in cancer progression

Malignant disease is characterized by a hemostatic imbalance, usually shifted towards a procoagulant direction, and a high incidence of thrombotic complications. The mechanisms of hemostasis that are critically involved in thrombosis are also implicated in tumor progression, angiogenesis, and metastatic spread. As there is a close relationship between cancer and the clotting system, circulating biomarkers of activation of various hemostasis compartments (i.e. coagulation, fibrinolysis, platelets, endothelium, and other blood cells) have been extensively studied to predict cancer outcomes along with predicting the thrombotic risk. In this review, we will summarize the results of published studies and will focus on ongoing research and future directions of clotting activation bioproducts as biomarkers of cancer disease and progression.

Continuous thrombin generation in whole blood: New applications for assessing activators and inhibitors of coagulation

Hemostatic tests have been utilized to clarify the blood coagulation potential. The novel thrombin generation (TG) assay of this study provides explicit information and is the most physiologically-relevant hemostatic test ex vivo. We describe how this assay allows for TG under a number of relevant circumstances. First, whole blood (WB) from healthy individuals was analyzed ± 5 pM tissue factor (TF) and ± contact pathway inhibition. Without an exogenous initiator TG was decreased and delayed, but addition of 5 pM TF shortened the lag phase and increased peak thrombin. Additional experiments included fresh WB from a trauma patient analyzed for endogenous activity and TG from healthy donors subjected to TG antagonists which prolonged the lag phase whereas TG agonists consistently shortened the lag phase in a dose dependent manner. Lastly, platelet-poor plasma was reconstituted with packed red blood cells and TG was monitored in the presence and absence of both TF as an activator and PCPS as a phospholipid surface. Our data illustrate the potential that this continuous TG assay has in the evaluation of disorders relevant to blood coagulation and in the monitoring of treatments administered in response to these disorders.