Jangsung (South Korea)

Bioabsorbable polymer-based drug-eluting stents have been shown to be effective and safe in the actual practice. The objective of the present study was to evaluate a biodegradable poly-L-lactic acid (PLLA)-based sirolimus-coated stent in comparison with a commercial everolimus-eluting stent with a permanent polymer in a porcine coronary restenosis model on a short-, mid-, and long-term basis. Pigs were randomized into eight groups in which the coronary arteries (36 pigs with 72 coronary arteries) had either a sirolimus-eluting stent with PLLA (SES, n=24, follow-up after 4, 12, and 24 weeks), bare metal stent (BMS, n=12, follow-up after 4 weeks), PLLA-coated stent without a drug (PCS, n=12, follow-up after 4 weeks), or commercial everolimus-eluting stent with a permanent polymer (EES, Promus PREMIER®, n=24, follow-up after 4, 12, and 24 weeks). Histopathological analysis was performed at 4, 12, or 24 weeks after stenting. The surface morphology of the SES, visualized using an optical microscope and a scanning electron microscope, was smooth and uniform with virtually no defects. Sirolimus was released slowly over 60 days. There was no significant difference in the percent area stenosis between the SES and EES at any of the follow-up time points (13.0±8.10% in SES vs. 14.1±9.12% in EES at 4 weeks, 23.1±8.63% in SES vs. 21.3±7.92% in EES at 12 weeks, 28.2±8.20% in SES vs. 25.1±8.51% in EES at 24 weeks, each p=NS). The percent area stenosis using micro-computed tomography and intravenous ultrasound demonstrated similar restenosis rates with histopathological stenosis between the SES and EES. The SES with a biodegradable polymer was as effective as the commercial EES with a permanent polymer in inhibiting neointima proliferation at 4, 12, and 24 weeks in a porcine coronary restenosis model.

The aim of this study was to evaluate antiproliferative sirolimus- and antioxidative alpha-lipoic acid (ALA)-eluting stents using biodegradable polymer [poly-L-lactic acid (PLA)] in a porcine coronary overstretch restenosis model. Forty coronary arteries of 20 pigs were randomized into four groups in which the coronary arteries had a bare metal stent (BMS, n = 10), ALA-eluting stent with PLA (AES, n = 10), sirolimus-eluting stent with PLA (SES, n = 10), or sirolimus- and ALA-eluting stent with PLA (SAS, n = 10). A histopathological analysis was performed 28 days after the stenting. The ALA and sirolimus released slowly over 30 days. There were no significant differences between groups in the injury or inflammation score; however, there were significant differences in the percent area of stenosis (56.2 ± 11.78% in BMS vs. 51.5 ± 12.20% in AES vs. 34.7 ± 7.23% in SES vs. 28.7 ± 7.30% in SAS, P < 0.0001) and fibrin score [1.0 (range 1.0-1.0) in BMS vs. 1.0 (range 1.0-1.0) in AES vs. 2.0 (range 2.0-2.0) in SES vs. 2.0 (range 2.0-2.0) in SAS, P < 0.0001] between the four groups. The percent area of stenosis based on micro-computed tomography corresponded with the restenosis rates based on histopathological stenosis in different proportions in the four groups (54.8 ± 7.88% in BMS vs. 50.4 ± 14.87% in AES vs. 34.5 ± 7.22% in SES vs. 28.9 ± 7.22% in SAS, P < 0.05). SAS showed a better neointimal inhibitory effect than BMS, AES, and SES at 1 month after stenting in a porcine coronary restenosis model. Therefore, SAS with PLA can be a useful drug combination for coronary stent coating to suppress neointimal hyperplasia.

Glucocorticoids are powerful anti-inflammatory, immunosuppressive, and anti-proliferative agents. The aim of this study was to evaluate the effectiveness of a prednisolone- (PDScs) and sirolimus-coated stent (SRLcs) in preventing artery vessel neointimal hyperplasia and inflammatory reactions invitro and invivo. PDS, a synthetic glucocorticoid, is a derivative of cortisol, which is used to treat a variety of inflammatory and autoimmune conditions. The stents were fabricated with PDS, SRL, or both agents using a layer-by-layer coating system (designated as PDScs, SRLcs, and PDSRLcs, respectively). The surface morphology of the PDScs showed an evenly dispersed and roughened shape, which was smoothened by the SRL coating. Half of the total drug amounts were released within seven days, followed by an additional release, which continued for up to 28 days. The proliferation of smooth muscle cells was inhibited in the SRLcs group (31.5 ± 4.08%), and this effect was enhanced by PDS addition (PDSRLcs, 46.8 ± 8.11%). Consistently, in the animal study, the restenosis rate was inhibited by the SRLcs and PDSRLcs (18.5 ± 6.23% and 14.5 ± 3.55%, respectively). Especially, fibrin expression and inflammation were suppressed in the PDS-containing group (PDScs, 0.6 ± 0.12 and 1.4 ± 0.33; PDSRLcs, 0.7 ± 0.48 and 1.7 ± 0.12, respectively) compared to PDS non-containing groups (BMS, 1.1 ± 0.12, and 1.8 ± 0.55; SRLcs, 1.6 ± 0.32 and 2.0 ± 0.62, respectively). Moreover, re-endothelialization was enhanced in the PDScs group as determined using immunohistochemistry with a cluster of differentiation (CD)-31 antibodies. These results suggest that the inhibitory effect of SRLcs on anti-restenosis can be accelerated by additional coating with PDS, which has promising properties as a bioactive compound with useful anti-inflammatory effects.

A fire took place in an indoor shooting range in Pusan, Korea, causing 15 deaths and 1 injury. To determine the cause of the fire, field investigation and laboratory analysis were conducted, and the point of ignition was determined through closed-circuit television (CCTV) imagery. Residues of ball powder, balloon, and stray bullet were found at the point of ignition. Moreover, the polyurethane slabs installed for sound absorption on the walls and ceiling surrounding the point of origin were found to lack any flame resistance. In tests of gunpowder ignition on the surface of the sound absorbers, the material ignited readily and the fire spread rapidly. Through analysis of CCTV at the time of ignition, any source of ignition related to human intervention could be ruled out. Considering the fact that ignition started immediately after shooting and the rubber plate for stray bullet protection had fallen off, we conclude that the most probable scenario is that a stray bullet landed on the sound absorber at the point of origin and ignited ball powder accumulated there, thus starting the fire. As a result of shooting 50 rounds of bullets, most bullet fragments dropped within 2 m of the bullet trap whereas two stray bullets reached 4.6 m and 1.3 m from the point of ignition. It was revealed that people at the indoor shooting range did not have sufficient time to evacuate. Although the fire lasted for a short time, victims were exposed to high temperatures, making visual identification difficult.