Effects of Rosuvastatin on Apolipoprotein J in Balloon-Injured Carotid Artery in Rats / Efeitos da Rosuvastatina sobre Apolipoproteína J em Artérias de Ratos Lesionadas com Balão

Abstract Background: Restenosis after percutaneous coronary intervention in coronary heart disease remains an unsolved problem. Clusterin (CLU) (or Apolipoprotein [Apo] J) levels have been reported to be elevated during the progression of postangioplasty restenosis and atherosclerosis. However, its role in neointimal hyperplasia is still controversial. Objective: To elucidate the role Apo J in neointimal hyperplasia in a rat carotid artery model in vivo with or without rosuvastatin administration. Methods: Male Wistar rats were randomly divided into three groups: the control group (n = 20), the model group (n = 20) and the statin intervention group (n = 32). The rats in the intervention group were given 10mg /kg dose of rosuvastatin. A 2F Fogarty catheter was introduced to induce vascular injury. Neointima formation was analyzed 1, 2, 3 and 4 weeks after balloon injury. The level of Apo J was measured by real-time PCR, immunohistochemistry and western blotting. Results: Intimal/medial area ratio (intimal/medial, I/M) was increased after balloon-injury and reached the maximum value at 4weeks in the model group; I/M was slightly increased at 2 weeks and stopped increasing after rosuvastatin administration. The mRNA and protein levels of Apo J in carotid arteries were significantly upregulated after rosuvastatin administration as compared with the model group, and reached maximum values at 2 weeks, which was earlier than in the model group (3 weeks). Conclusion: Apo J served as an acute phase reactant after balloon injury in rat carotid arteries. Rosuvastatin may reduce the neointima formation through up-regulation of Apo J. Our results suggest that Apo J exerts a protective role in the restenosis after balloon-injury in rats.

Resumo Fundamento: A reestenose após intervenção coronária percutânea (ICP) após doença coronariana continua um problema não solucionado. Estudos relataram que os níveis de clusterina (CLU), também chamada de apolipoproteína (Apo) J, encontram-se elevados na progressão da reestenose pós-angioplastia e na aterosclerose. Contudo, seu papel na hihperplasia neointimal ainda é controverso. Objetivo: Elucidar o papel da Apo J na hiperplasia neointimal na artéria carótida utilizando um modelo experimental com ratos in vivo, com e sem intervenção com rosuvastatina. Métodos: ratos Wistar machos foram divididos aleatoriamente em três grupos - grupo controle (n = 20), grupo modelo (n = 20), e grupo intervenção com estatina (n = 32). Os ratos no grupo intervenção receberam 10 mg/kg de rosuvastatina. Um cateter Fogarty 2 F foi introduzido para induzir lesão vascular. A formação de neoíntima foi analisada 1, 2, 3 e 4 semanas após lesão com balão. Concentrações de Apo J foram medidas por PCR em tempo real, imuno-histoquímica e western blotting. Resultados: A razão área íntima/média (I/M) aumentou após a lesão com balão e atingiu o valor máximo 4 semanas pós-lesão no grupo modelo; observou-se um pequeno aumento na I/M na semana 2, que cessou após a administração de rosuvastatina. Os níveis de mRNA e proteína da Apo J nas artérias carótidas aumentaram significativamente após administração de rosuvastatina em comparação ao grupo modelo, atingindo o máximo na semana 2, mais cedo em comparação ao grupo modelo (semana 3). Conclusão: A Apo J atuou como reagente de fase aguda após lesão com balão nas artérias carótidas de ratos. A rosuvastatina pode reduzir a formação de neoíntoma por aumento de Apo J. Nossos resultados sugerem que a Apo J exerce um papel protetor na reestenose após lesão com balão em ratos.

Comparisons of the Effects of Stent Eccentricity on the Neointimal Hyperplasia between Sirolimus-Eluting Stent versus Paclitaxel-Eluting Stent

PURPOSE: Previous studies suggested that asymmetric stent expansion did not affect suppression of neointimal hyperplasia (NIH) after sirolimus-eluting stents (SES) implantation. The aim of this study was to evaluate the effects of stent eccentricity (SE) on NIH between SES versus paclitaxel-eluting stents (PES) using an intravascular ultrasound (IVUS) analysis from the randomized trial. MATERIALS AND METHODS: Serial IVUS data were obtained from Post-stent Optimal Expansion (POET) trial, allocated randomly to SES or PES. Three different SE (minimum stent diameter divided by maximum stent diameter) were evaluated; SE at the lesion site with maximal %NIH area (SE-NIH), SE at the minimal stent CSA [SE-minimal stent area (SE-MSA)], and averaged SE through the entire stent (SE-mean). We classified each drug-eluting stents (DES) into the concentric (> or = mean SE) and eccentric groups (< mean SE) based on the mean value of SE. RESULTS: Among 301 enrolled patients, 233 patients [SES (n = 108), PES (n = 125)] underwent a follow-up IVUS. There was no significant correlation between %NIH area and SE-NIH (r = - 0.083, p = 0.391) or SE-MSA (r = - 0.109, p = 0.259) of SES. However, SE-NIH of PES showed a weak but significant correlation with %NIH area (r = 0.269, p < 0.01). As to the associations between SE-mean and NIH volume index, SES revealed no significant correlation (r = - 0.001, p = 0.990), but PES showed a weak but significant correlation (r = 0.320, p < 0.01). However, there was no difference in the restenosis rate between the eccentric versus concentric groups of both DES. CONCLUSION: This study suggests that lower SE of both SES and PES, which means asymmetric stent expansion, may not be associated with increased NIH.

Pathology of drug-eluting stents: implications for coronary intervention.

BACKGROUND: Polymer-based sirolimus (Cypher) and paclitaxel (Taxus) drug-eluting stents (DES) have become the treatment of choice for patients with symptomatic coronary artery disease. While these stents have reduced rates of restenosis and target lesion revascularization compared with bare metal stents (BMS), late thrombosis [i.e. stent thrombosis occurring > 30 days after percutaneous coronary intervention (PCI)], an often life-threatening complication, has emerged as a major safety concern. METHODS AND RESULTS: Using human pathological data, we have demonstrated that the current generation US Food and Drug Administration (FDA) Cypher and Taxus DES cause substantial impairment of arterial healing, defined as impaired re-endothelialization, persistent fibrin deposition, and absence or focal presence of smooth muscle cells covering the stent struts compared with BMS. This delay in healing constitutes the most important pathological substrate underlying cases of late DES thrombosis. CONCLUSIONS: This review will focus on the effects of these vascular implants in both animals and humans, especially as they relate to the process of late-stent thrombosis. We will use these data to make practical recommendations regarding anatomic and lesion considerations that may help the interventionalist to minimize the late thrombotic risk of these devices.

Análise ultra-sonográfica da resposta vascular tardia das bordas de stents liberadores de drogas análogas ao sirolimus: comparação entre diabéticos e não-diabéticos / IVUS analysis of the late vascular response at the edges of sirolimus analogue-eluting stents: comparison among diabetic and non-diabetic patients

Introdução: A resposta vascular dos segmentos adjacentes aos stents liberadores de medicamentos continua sendo objeto de estudo, principalmente nos pacientes diabéticos (DM), nos quais a progressão da aterosclerose é mais freqüentemente observada. Recentemente, os fármacos Biolimus e Zotarolimus demonstraram eficácia semelhante ao Sirolimus na redução da hiperplasia intimal intra-stent. Objetivo: Comparar a resposta vascular tardia nas bordas proximais (BP) e distais (BD), entre DM e não-diabéticos (NDM) tratados com stents liberadores de sirolimus ou fármacos análogos (Biolimus e Zotarolimus), avaliada pelo ultra-som intracoronário (USIC). Método: Foram incluídos 153 pacientes (306 bordas) tratados com stents (53% Sirolimus, 26% Zotarolimus e 21% Biolimus) e divididos em dois grupos em relação à presença de diabetes: DM, 122 bordas e NDM, 166 bordas; 18 bordas foram excluídas. As análises pelo USIC foram realizadas nos 5 mm proximal e distal aos stents após o implante (basal) e no seguimento tardio (± 6 meses). Os volumes do vaso (VV), do lúmen (VL) e da placa (VP) foram calculados pela regra de Simpson. A porcentagem de obstrução (% Obs) e a variação dos volumes (Delta - Δ) entre seguimento e basal foram também calculados. Reestenose das bordas foi definida como uma obstrução >50% no seguimento. Resultados: A media para idade foi 58±9 anos, sendo 59% do sexo masculino. Não houve diferença nas características basais dos grupos...

Introduction: Late vascular response of the segments adjacent to proximal and distal edges of the drug-eluting stents is still not well established, particularly in diabetic patients who are prone to atherosclerosis plaque progression. Recently, new sirolimus-analogue eluting stents (Biolimus and Zotarolimus) have demonstrated potent antiproliferative effects. Objective: To compare the late vascular responses at proximal (PE) and distal (DE) edges of sirolimus analogue-eluting stents in patients with and without diabetes (DM or NDM) using intravascular ultrasound (IVUS). Method: 306 IVUS edge analyses were performed in 153 patients treated with drug-eluting stents(53% Sirolimus, 26% Zotarolimus, 21% Biolimus). Patients were divided in two groups: DM, 122 edges and NDM, 166 edges; 18 edges were excluded. IVUS analyses were performed post-intervention (PI) and after 6-month follow-up (FU) and included 5 mm distal and proximal to the stented segment. Vessel, lumen and plaque volumes were calculated by Simpon’s rule. Percentage of obstruction and volumes changes (FUminus PI values) were also calculated. Edge restenosis was defined as obstruction >50% at FU. Results: The mean age was 58±9 y, and 59% were male. The baseline characteristics were similar between groups. In both groups, the entire lesion length was totally covered (stent length / lesion length was 1.51 and 1.52). There were no significant differences in edge volumes between the two groups...

Differential local effect of sirolimus eluting stent and paclitaxel eluting stent in a porcine restenosis model

Introdução: Os stents farmacológicos liberadores de sirolimus (SES) e de paclitaxel (PES) reduzem de maneira significativa os índices de reestenose se comparados aos stents de metal. Há muita controvérsia com relação aos possíveis efeitos indesejáveis do SES e do PES, como, por exemplo, a trombosesubaguda intra-stent. Este estudo teve como objetivo comparar o efeito arterial local do SES e do PES. Métodos: A dilatação coronariana foi induzida em 16 suínos pela insuflação de um balão superdimensionado na proporção 1.2:1.0 em 43 artérias. Foram olocados aleatoriamente 21 SES e 22 PES na descendente anterior esquerda e na circunflexa esquerda no local da lesão anterior por balão. Os animais foramenviados para necropsia 30 dias após o procedimento. Vinte artérias foram enviadas para análise pelo métodoWestern Blot (16 segmentos com stent + 4 controles normais). Vinte e sete segmentos com stent foram submetidos à análise histológica e à microscopia eletrônica (ME) a baixo vácuo. Resultados: Não foram observadas diferenças com referência às características morfométricas entre os dois grupos. A espessura neointimal se mostrou semelhante nos segmentos com stent SES e PES (0,23±0,05mm vs 0,21±0,08mm, respectivamente – p=0,08). A cicatrização arterial localavaliada pelo método WB demonstrou níveis significantemente mais altos do fator Von Willebrand e CD 31 em SESvs PES (p=0,005 e 0,03, respectivamente). PES demonstrou,ainda, inflamação local mais intensa, expressa pelos níveis mais altos de PDGF (p=0,0007). Este resultado foi corroborado pelos achados de reação inflamatória local mais intensa pela ME, expressa por dados inflamatórios mais elevados no grupo PES. Conclusão: PES demonstrou maior grau de inflamação e menor expressão de CD31 e do fator VonWillebrand, sugerindo, portanto, cicatrização endotelial comprometidaapós a colocação do stent se comparado ao SES.

Background: Sirolimus eluting stents (SES) and Paclitaxel eluting stents (PES) significantly reduce restenosis rates as compared with bare metal stents. There is much controversyregarding possible untoward effects of SES and PES such as subacute stent thrombosis. The present study aimed tocompare the local arterial effect of SES versus PES. Methods: In 16 pigs coronary overstretch was induced by inflating an oversized angioplasty balloon at 1.2:1.0 ratio in 43 arteries. Twenty one SES and 22 PES were randomly deployed in LAD and LCx in the site of previous balloon injury. Animals were sent to necropsy 30 days after the procedure. Twenty arteries were sent to Western Blot (WB) analysis (16 stented segments plus 4 normal controls). Twenty seven stented segments were submitted to histologyanalysis and low vacuum electron microscopy (EM). Results: There were no differences regarding arterial morphometric characteristics between the two groups. Neo intimal thicknesswere similar in SES and PES stented segments (0.23±0.05mm vs 0.21±0.08mm, respectively – p=0.08). Local arterial healing assessed by WB showed significantly higher local levels of Von Willebrand factor and CD 31 in SES vs PES (p values of 0.005 and 0.03, respectively). Also, PES showed higher local inflammation as expressed byhigher PDGF levels (p= 0.0007). This result was corroborated by the EM findings of higher local inflammatory reaction, expressed by higher inflammation scores in the PES group.Conclusion: PES showed higher inflammation and lower expression of CD31 and Von Willebrand factor, suggesting an impaired endothelial healing after stenting when comparedwith SES.