Structure and Function of Trypsin-Loaded Fibrinolytic Liposomes

Biomed Res Int. 2017:2017:5130495. doi: 10.1155/2017/5130495. Epub 2017 Jul 3.

Abstract

Protease encapsulation and its targeted release in thrombi may contribute to the reduction of haemorrhagic complications of thrombolysis. We aimed to prepare sterically stabilized trypsin-loaded liposomes (SSLT) and characterize their structure and fibrinolytic efficiency. Hydrogenated soybean phosphatidylcholine-based SSLT were prepared and their structure was studied by transmission electron microscopy combined with freeze fracture (FF-TEM), Fourier transform infrared spectroscopy (FT-IR), and small-angle X-ray scattering (SAXS). Fibrinolytic activity was examined at 45, 37, or 24°C on fibrin or plasma clots with turbidimetric and permeation-driven lysis assays. Trypsin was shown to be attached to the inner surface of vesicles (SAXS and FF-TEM) close to the lipid hydrophilic/hydrophobic interface (FT-IR). The thermosensitivity of SSLT was evidenced by enhanced fibrinolysis at 45°C: time to reduce the maximal turbidity to 20% decreased by 8.6% compared to 37°C and fibrin degradation product concentration in the permeation lysis assay was 2-fold to 5-fold higher than that at 24°C. SSLT exerted its fibrinolytic action on fibrin clots under both static and dynamic conditions, whereas plasma clot dissolution was observed only in the permeation-driven assay. The improved fibrinolytic efficiency of SSLT under dynamic conditions suggests that they may serve as a novel therapeutic candidate for dissolution of intravascular thrombi, which are typically exposed to permeation forces.

MeSH terms

  • Fibrinolysis / drug effects*
  • Fibrinolytic Agents / chemistry
  • Fibrinolytic Agents / pharmacology*
  • Humans
  • Liposomes
  • Structure-Activity Relationship
  • Thrombolytic Therapy / methods*
  • Trypsin / chemistry
  • Trypsin / pharmacology*

Substances

  • Fibrinolytic Agents
  • Liposomes
  • Trypsin