Micropatterning of a 2-methacryloyloxyethyl phosphorylcholine polymer surface by hydrogenated amorphous carbon thin films for endothelialization and antithrombogenicity.

The existing first-generation drug-eluting stent (DES) has caused late and very late stent thrombosis related to incomplete stent endothelialization. Hence, biomaterials that possess sufficient anti-thrombogenicity and endothelialization with the controlled drug release system have been highly required. In this work, we have developed a newly designed drug-release platform composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, a non-thrombogenic polymer, and micropatterned hydrogenated amorphous carbon (a-C:H), a cell-compatible thin film. The platelet adhesion and the endothelial cell adhesion behavior on the micropatterned substrates were investigated in vitro. The results indicated that the micropatterned a-C:H/MPC polymer substrates effectively supported the human umbilical vein endothelial cell (HUVEC) proliferation, while suppressing the platelet adhesion. Interestingly, the HUVEC exhibited different shape and behavior by changing the island size of the micropatterned a-C:H. By introducing both a non-thrombogenic polymer and cell-compatible thin films through a simple patterning method, we demonstrated that the platform had the potential to be utilized as a base material for DES with cell controllability. STATEMENT OF SIGNIFICANCE: The current first-generation drug-eluting stents (DES) would cause late and very late stent thrombosis due to the incomplete endothelialization of the metal stent material. In this work, we have developed a new DES platform composed of a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer micropatterned by hydrogenated amorphous carbon (a-C:H). Two types of differently micropatterned a-C:H stent surface were made. Our studies revealed that the micropatterned a-C:H/MPC polymer substrates could effectively enhance the endothelial cell (EC) proliferation, simultaneously suppressing the platelet adhesion, becoming a highly biocompatible material especially for indwelling devices including a drug-release device. The new drug-release platform could be utilized as a base material for cell-controllable coating on DES.

Lymphangiography and Post-lymphangiographic Multidetector CT for Preclinical Lymphatic Interventions in a Rabbit Model.

PURPOSE: To describe the feasibility of lymphangiography and the visibility of the lymphatic system using post-lymphangiographic multidetector CT (MDCT) for preclinical lymphatic interventions in a rabbit model. MATERIALS AND METHODS: Lymphangiography via the popliteal lymph node or vessel after surgical exposure was performed, using six healthy female Japanese White rabbits. Lipiodol was manually injected for lymphangiography. Post-lymphangiographic MDCT examinations were performed in all rabbits. The dataset images were subjected to image processing analysis utilizing the three-dimensional maximum intensity projection technique. Three reviewers evaluated the degree of depiction of the lymphatic system using a four-point visual score (1, poor; 2, fair; 3, good; 4, excellent). The distance between the body surface and cisterna chyli was measured on post-lymphangiographic MDCT axial image. RESULTS: Lymphangiography was successfully performed in all rabbits. The popliteal lymph node was detectable in 90%. The visualization of lymphatic system via the popliteal node was achieved in 89%. Mean visual scores of > 3.0 were realized by the right femoral lymphatic vessel, left femoral lymphatic vessel, left iliac lymphatic vessel, left lumbar lymphatic trunks and cisterna chyli, whereas mean visual scores of < 3.0 were yielded by the right iliac lymphatic vessel, right lumbar lymphatic trunks and thoracic duct. The distance between the body surface and cisterna chyli on post-lymphangiographic MDCT axial images was 4.33 ± 0.14 cm. CONCLUSION: Lymphangiography is feasible, and the visibility of the lymphatic system on post-lymphangiographic MDCT in a rabbit model provides enough information for interventional radiologists to perform preclinical lymphatic interventions.

Microballoon-related interventions in various endovascular treatments of body trunk lesions.

Occlusion balloon catheters of 5.2- or 6-French have been used for a few decades in various endovascular treatments of body trunk vascular lesions. However, these catheters may be difficult to place in cases of excessive vessel tortuosity, small vessels, and anatomic complexity. Recently, the introduction of the double lumen microballoon catheters for body trunk vascular lesions has allowed operators to advance them into more distal, smaller, and more tortuous vessels. Since the launch of the first generation microballoon catheters onto the market in Japan in 2011, the microballoon catheters have evolved and are now generally available for clinical use. The purpose of this article is to review the evolution and current clinical applications of the microballoon catheters in the field of interventional radiology.

In vitro basic fibroblast growth factor (bFGF) delivery using an antithrombogenic 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer coated with a micropatterned diamond-like carbon (DLC) film.

In this study, a newly designed drug-release platform composed of an antithrombogenic 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer was introduced, which was impregnated with basic fibroblast growth factor (bFGF) (bFGF/MPC polymer) to enhance the endothelial cell activation. The platform was also coated with an ultrathin micropatterned diamond-like carbon (DLC) film (DLC/bFGF/MPC polymer) to precisely control the drug release rate and the cell compatibility. The resulting DLC/bFGF/MPC polymer could effectively prolong the bFGF release rate by depositing the micropatterned DLC. The number of adherent platelets on the DLC/bFGF/MPC polymer was significantly lower (about 1/14) than that on a currently used stent made of stainless steel (SUS316L), indicating the enhanced antithrombogenicity in the DLC/bFGF/MPC polymer. The proliferation of endothelial cells on the DLC/bFGF/MPC polymer and the DLC/MPC polymer (without bFGF) were also examined. It was found that the optical density of HUVEC on the DLC/bFGF/MPC polymer determined by WST-8 assay was higher by 25%than that on the DLC/MPC polymer (without bFGF) measured after 72 h of incubation. Our results suggest that the released bFGF that contributes to the expression of other growth factors results in the early proliferation of the HUVEC on the DLC/bFGF/MPC polymer. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3384-3391, 2017.