Rapamycin Combined with α-Cyanoacrylate Contributes to Inhibiting Intimal Hyperplasia in Rat Models / Rapamicina em Combinação com α-Cianoacrilato Contribui à Inibição de Hiperplasia Intimal em Modelos em Ratos

Abstract Background: Vein graft restenosis has an adverse impact on bridge vessel circulation and patient prognosis after coronary artery bypass grafting. Objectives: We used the extravascular supporter α-cyanoacrylate (α-CA), the local application rapamycin/sirolimus (RPM), and a combination of the two (α-CA-RPM) in rat models of autogenous vein graft to stimulate vein graft change. The aim of our study was to observe the effect of α-CA, RPM, and α-CA-RPM on vein hyperplasia. Methods: Fifty healthy Sprague Dawley (SD) rats were randomized into the following 5 groups: sham, control, α-CA, RPM, and α-CA-RPM. Operating procedure as subsequently described was used to build models of grafted rat jugular vein on carotid artery on one side. The level of endothelin-1 (ET-1) was determined by enzyme-linked immunosorbent assay (ELISA). Grafted veins were observed via naked eye 4 weeks later; fresh veins were observed via microscope and image-processing software in hematoxylin-eosin (HE) staining and immunohistochemistry after having been fixed and stored" (i.e. First they were fixed and stored, and second they were observed); α-Smooth Muscle Actin (αSMA) and von Willebrand factor (vWF) were measured with reverse transcription-polymerase chain reaction (RT-PCR). Comparisons were made with single-factor analysis of variance and Fisher's least significant difference test, with p < 0.05 considered significant. Results: We found that intimal thickness of the α-CA, RPM, and α-CA-RPM groups was lower than that of the control group (p < 0.01), and the thickness of the α-CA-RPM group was notably lower than that of the α-CA and RPM groups (p < 0.05). Conclusion: RPM combined with α-CA contributes to inhibiting intimal hyperplasia in rat models and is more effective for vascular patency than individual use of either α-CA or RPM.

Resumo Fundamento: Reestenose de enxertos venosos tem um impacto adverso na circulação de pontagens e no prognóstico de pacientes após a cirurgia de revascularização miocárdica. Objetivos: Nós utilizamos α-cianoacrilato (α-CA) como suporte extravascular, rapamicina/sirolimus (RPM) como aplicação local e a combinação dos dois (α-CA-RPM) em modelos de enxerto venoso autógeno em ratos para estimular mudança no enxerto venoso. O objetivo do nosso estudo foi observar o efeito de α-CA, RPM e α-CA-RPM na hiperplasia venosa. Métodos: Cinquenta ratos Sprague Dawley (SD) saudáveis foram randomizados nos 5 grupos seguintes: sham, controle, α-CA, RPM e α-CA-RPM. O procedimento operacional descrito subsequentemente foi utilizado para construir modelos de enxertos da veia jugular na artéria carótida em ratos, em um lado. O nível de endotelina-1 (ET-1) foi determinado por ensaio de imunoabsorção enzimática (ELISA). As veias enxertadas foram observadas a olho nu 4 semanas após; as veias frescas foram observadas via microscópio e software de processamento de imagem com coloração hematoxilina-eosina (HE) e imuno-histoquímica depois de serem fixadas e armazenadas; α-actina do músculo liso (αSMA) e o fator de von Willebrand (vWF) foram medidos com reação em cadeia da polimerase-transcriptase reversa (RT-PCR). Realizaram-se as comparações com análise de variância de fator único (ANOVA) e o teste de diferença mínima significativa (LSD) de Fisher, com p < 0,05 sendo considerado estatisticamente significante. Resultados: Nós achamos que a espessura intimal nos grupos α-CA, RPM e α-CA-RPM era menor que no grupo controle (p < 0,01) e a espessura no grupo α-CA-RPM era notavelmente menor que nos grupos α-CA e RPM (p < 0,05). Conclusão: A combinação de RPM e α-CA contribui à inibição de hiperplasia em modelos em ratos e é mais efetivo para patência vascular que uso individual de α-CA ou RPM.

Biomodelo de insuficiencia renal crónica con el uso del tisuacryl en ratas / Chronic renal failure model with the use of tisuacryl in rats

Introducción: con el propósito de mejorar la atención a la Insuficiencia Renal Crónica (IRC) como problema de salud, se han desarrollado numerosas investigaciones experimentales en biomodelos. Perfeccionar los biomodelos de IRC, es uno de los retos actuales. Los biomodelos de IRC quirúrgicos son los más utilizados y entre sus variantes se deben favorecer la precisión en la instauración y evolución con respecto al tiempo de la insuficiencia. Objetivo: evaluar un modelo experimental de Insuficiencia Renal Crónica en ratas con el uso del Tisuacryl. Método: para ello se utilizaron 90 ratas Wistar distribuidas en series (de 7, 28, 42, y 60 días) y grupos de trabajo (controles y experimentales) para cada serie. Se diseñó un modelo de IRC por ablación de 5/6 de la masa renal y se utilizó el adhesivo tisular Tisuacryl de producción nacional como sellante de las superficies de corte. Se evaluaron la proteinuria de 24 horas, creatinina plasmática, flujo plasmático renal efectivo (FPRE), intensidad de filtración glomerular (IFG) y la fracción de filtración. Resultados: se apreció un aumento de la Proteinuria y la Creatinina y una caída del flujo plasmático renal efectivo y la intensidad de filtración glomerular. Todas las variables caracterizaron la instauración de una insuficiencia renal crónica en el modelo con un grado de moderado a ligero con estabilidad. Conclusiones: se evaluó un modelo de Insuficiencia Renal Crónica en ratas con el uso del Tisuacryl, lo que ha permitido comprobar cómo este modelo ha llegado a replicar las condiciones en humanos. Se determinan como variables fundamentales para indicar la evaluación del grado de Insuficiencia la proteinuria, la creatinina plasmática, el FPRE y IFG, justificando el grado de insuficiencia, los cuales transitan para este modelo por moderado y ligero.

Introduction: to provide better health care to renal failure patients is a national health goal in our country; thus, different studies have been carried out using biomodels for renal failure. To improve the reliability of these biomodels still remains as a major challenge. Particularly, models for chronic renal failure (CRF) have been widely used, pursuing a better accuracy in instauration and evolution time, especially in defining the failure's duration. Objective: to validate an experimental model for CRF in rats using Tisuacryl developed in our laboratory. Methods: ninety Wistar rats were distributed into series (of 7, 28, 42, and 60 days) and working groups (controls and experimental) for each series. CRF model for ablation of 5/6 of the renal mass was designed, using the tissue adhesive Tisuacryl (of national production) as sealant of the cut surfaces. The following parameters were evaluated: protein excretion during 24 hours, plasmatic creatinine, renal effective plasmatic flow (REPF), glomerular filtration rate (GFR), and filtration fraction. Results: an increase in protein excretion and creatinine was observed, as well as a drop in, REPF, and GFR. All variables changed to levels compatible with a scenario of CRF of moderate to slight stability level. Conclusions: the Tisuacryl rat model for CRF was evaluated. As result, this model reproduces the conditions of the disease in humans. The best variables for describing the CRF were: protein excretion, plasma creatinine, REPF and GFR, since these allow assessing the failure's degree. In this model the failure degree transits from slight to moderate.