Graft Product for Autologous Peripheral Blood Stem Cell Transplantation Enhances Thrombin Generation and Expresses Procoagulant Microparticles and Tissue Factor

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.

Magnetic Accumulation of SPIONs under Arterial Flow Conditions: Effect of Serum and Red Blood Cells

Magnetic drug targeting utilizes an external magnetic field to target superparamagnetic iron oxide nanoparticles (SPIONs) and their cargo to the diseased vasculature regions. In the arteries, the flow conditions affect the behavior of magnetic particles and the efficacy of their accumulation. In order to estimate the magnetic capture of SPIONs in more physiological-like settings, we previously established an ex vivo model based on human umbilical cord arteries. The artery model was employed in our present studies in order to analyze the effects of the blood components on the efficacy of magnetic targeting, utilizing 2 types of SPIONs with different physicochemical characteristics. In the presence of freshly isolated human plasma or whole blood, a strong increase in iron content measured by AES was observed for both particle types along the artery wall, in parallel with clotting activation due to endogenous thrombin generation in plasma. Subsequent studies therefore utilized SPION suspensions in serum and washed red blood cells (RBCs) at hematocrit 50%. Interestingly, in contrast to cell culture medium suspensions, magnetic accumulation of circulating SPION-3 under the external magnet was achieved in the presence of RBCs. Taken together, our data shows that the presence of blood components affects, but does not prevent, the magnetic accumulation of circulating SPIONs.