The objective of this experimental study was to assess the effects of a new kind of drug eluting coronary stent. Fourteen mini-pigs were used; seven normal stainless stents and seven new drug eluting stents were implanted in their normal coronary arteries, respectively. Angiography was performed and followed by pressure-fixation of the coronary arteries for light and electron microscopic examinations at the end of three months after implantation. Repeated angiography showed that all the stented coronary segments were open. With no additional antithrombotic treatment, there was no thrombus formed in the stented coronary segments. Scanning electron microscopy analysis showed the implanted stent surface was covered by endomembrane without thrombus formation. The endothelial cell in the membrane was clear and lined by the direction of blood flow. Histomorphological analysis revealed the neointima in normal stainless stent group was thicker than that in new drug eluting stent group, and the neointima was composed of smooth muscle cell and extracellular matrix. The result of this study shows that this kind of stent could reduce the rate of the re-stenosis and occlusion of PTCA. This stent can be used in clinical trials.
Angioplasty, Balloon, Coronary ; instrumentation ; Animals ; Coated Materials, Biocompatible ; chemistry ; Coronary Restenosis ; prevention & control ; Drug-Eluting Stents ; Random Allocation ; Swine ; Swine, Miniature ; Titanium ; chemistry

In this research,enzyme linked immunoassay (ELISA) was used to assay the fibrinogen (FIG) adsorbed on the Ti-O films and on the low temperature isotropic carbon (LTIC) films which were planted in the femoral arteries of 6 mongrel dogs for six months, respectively. The Ti-O films were planted in the dogs' left femoral arteries; the LTIC films as controls were planted in the dogs' right femoral arteries. The contents adsorbed in these two kinds of films were examined by scanning electron microscopy (SEM). The quantities of FIG adhered or denatured on the Ti-O films or LTIC films determined by ELISA, and the platelets adhered on the two kinds of films examined by SEM were of significant difference between the two groups. In the blood vessel, the amount of FIG adhered on biomaterial was related to its component and construction. FIG released electron to the biomaterial and induced the unfolding of C term of the gamma-chain of FIG, and the conjugation point and effect point were exposed. In conclusion, the biomaterial, which has the capability for resisting the electron release from FIG as well as for maintaining the invariable electric condition, will have excellent hemocompatibility.
Adsorption ; Animals ; Dogs ; Fibrinogen ; metabolism ; Heart Valve Prosthesis ; Histocompatibility ; Molecular Conformation ; Platelet Adhesiveness ; Prostheses and Implants ; Surface Properties ; Titanium ; chemistry

The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.
Albumins ; chemistry ; Animals ; Coated Materials, Biocompatible ; pharmacology ; Dogs ; Fibrinogen ; chemistry ; Heparin ; chemistry ; Materials Testing ; methods ; Prosthesis Design ; Stents ; Surface Properties ; Titanium ; chemistry

This experiment was designed to investigate the influence of two biomaterials, titanium oxide (Ti-O) and stainless steel (SS), on the cytokine expression of macrophage, and further, to evaluate their biocompatibility. After being co-cultured with Ti-O and SS for 72 h, the cell number and morphology of macrophages attached on materials were detected by fluorescent microscope and SEM. Nitride oxide (NO) and monocyte chemoattractant protein 1 (MCP-1) released by the macrophages co-cultured with different materials were also examined and compared. We found that the cell number of macrophages attached to Ti-O was smaller than that attached to SS. The levels of NO and MCP-1 released by the macrophages co-cultured with Ti-O were lower when compared with those released by macrophages co-cultured with SS. These results demonstrate that Ti-O has better biocompatibility than does SS.
Animals ; Biocompatible Materials ; pharmacology ; Cells, Cultured ; Chemokine CCL2 ; metabolism ; Macrophages ; cytology ; metabolism ; Male ; Materials Testing ; methods ; Nitric Oxide ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stainless Steel ; pharmacology ; Titanium ; pharmacology