[Three-dimensional printed 316L stainless steel cardiovascular stent's electrolytic polishing and its mechanical properties].

The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0-10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.

Impact of inverse unequal height strut structure on the functional performance of an additively manufactured cardiovascular stent.

Recently, additive manufacturing (AM) has been investigated as an innovative method to manufacture stents due to its capability in producing complex and customized structures. In this paper, the cardiovascular stents of M-type and N-type with inverse unequal height strut structure and N-type with equal height strut structure were designed and manufactured by Selective Laser Melting (SLM). Following surface polishing, balloon expansion, plane compression and three-point bending experiments were carried out to evaluate the mechanical performance of the stent. The stents designed with inverse unequal height strut structure showed higher radial support performance and lower radial recoil when compared to the stents with uniform design. This study proved the feasibility of SLM in rapid manufacturing of cardiovascular stents that can be used for performance evaluation in design stage.

Valsartan Regulates PI3K/AKT Pathways through lncRNA GASL1 to Improve Isoproterenol-Induced Heart Failure.

OBJECTIVE: This study is aimed at determining the expression and function of the GASL1 and PI3K/AKT pathways in isoproterenol- (ISO-) induced heart failure (HF). To determine the moderating effect of valsartan (VAL) on the progression of ISO-induced HF and to elucidate the related mechanism. MATERIALS AND METHODS: First, in in vivo experiment, we examined the effect of VAL on cardiac function in rats with ISO-induced HF. Similarly, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to detect the effect of VAL on ISO-treated rat primary cardiomyocytes. Then, si-GASL1-transfected primary cardiomyocytes were constructed and Ad-si-GASL1 was injected through rat tail vein to achieve the effect of lowering GASL1 expression, so as to investigate the role of GASL1 in VAL's treatment of ISO-induced HF. RESULTS: In ISO-induced HF rat models, the GASL1 decreased while PI3K and p-AKT expressions were abnormally elevated and cardiac function deteriorated, and VAL was able to reverse these changes. In primary cardiomyocytes, ISO induces apoptosis of cardiomyocytes, and expression of GASL1 decreased while PI3K and p-AKT were abnormally elevated, which can be reversed by VAL. The transfection of primary cardiomyocytes with si-GASL1 confirmed that GASL1 affected the expression of PI3K, p-AKT, and the apoptosis of primary cardiomyocytes. Rat myocardium injected with Ad-si-GASL1 was found to aggravate the cardiac function improved by VAL. CONCLUSIONS: This study was the first to confirm that VAL improves ISO-induced HF by regulating the PI3K/AKT pathway through GASL1. And this study demonstrated a significant correlation between HF, VAL, GASL1, and the PI3K/AKT pathway.

Review fantastic medical implications of 3D-printing in liver surgeries, liver regeneration, liver transplantation and drug hepatotoxicity testing: A review.

The epidemiological trend in liver diseases becomes more serious worldwide. Several recent articles published by International Journal of Surgery in 2018 particularly emphasized the encouraging clinical benefits of hepatectomy, liver regeneration and liver transplantation, however, there are still many technical bottlenecks underlying these therapeutic approaches. Remarkably, a few preliminary studies have shown some clues to the role of three-dimensional (3D) printing in improving traditional therapy for liver diseases. Here, we concisely elucidated the curative applications of 3D-printing (no cells) and 3D Bio-printing (with hepatic cells), such as 3D-printed patient-specific liver models and devices for medical education, surgical simulation, hepatectomy and liver transplantation, 3D Bio-printed hepatic constructs for liver regeneration and artificial liver, 3D-printed liver tissues for evaluating drug's hepatotoxicity, and so on. Briefly, 3D-printed liver models and bioactive tissues may facilitate a lot of key steps to cure liver disorders, predictably bringing promising clinical benefits. This work further provides novel insights into facilitating treatment of hepatic carcinoma, promoting liver regeneration both in vivo and in vitro, expanding transplantable liver resources, maximizing therapeutic efficacy as well as minimizing surgical complications, medical hepatotoxicity, operational time, economic costs, etc.